After he was convicted by a jury in the Superior Court of rape, the defendant moved for a new trial on *267the ground that he had been denied effective assistance of counsel. After an evidentiary hearing, the Superior Court judge who presided at trial denied the motion. The Appeals Court reversed, 28 Mass. App. Ct. 417 (1990), and we granted the Commonwealth’s application for further appellate review. We affirm the decision of the Superior Court.
We summarize the evidence at trial. The defendant and the complainant were employees of the Motorola Corporation. On August 19, 1987, following an employee meeting, a group of Motorola employees, including the defendant and the complainant, went to the cocktail lounge of a local hotel. Sometime after midnight, the defendant and the complainant left the lounge and walked together toward their respective cars in the hotel parking lot. Their stories diverge at this point. The complainant testified that the defendant forced her into the back seat of his car and raped her. The defendant testified that the complainant willingly entered his automobile and engaged in consensual sexual intercourse.
The complainant testified that she finally broke away from the defendant and drove home. She then called her husband, who was on business in California.1 Later that day, she called a Motorola personnel manager, Collette Wiggins, and said that she wanted to file a sexual harassment claim against the defendant. She told Wiggins that the defendant had forcibly fondled her, but that she had escaped. After this conversation, James Kelly, a Motorola vice president, called the complainant. The complainant repeated essentially the same story that she had related to Wiggins. That afternoon, the complainant called a friend, Pat Noguera, and reported that she had been raped.
The following day, the complainant met with both Wiggins and Kelly and reported that, in fact, she had been raped. The same day, the complainant also reported to the police that she had been raped. Noguera and the police officer with *268whom the complainant spoke testified as fresh complaint witnesses.2 As to physical evidence, the complainant’s panty hose (which had a run in the crotch) were admitted, as were photographs of bruises on the complainant’s legs that she testified resulted from the defendant kneeling on her.
The defendant’s case included his own testimony that intercourse had been consensual. The defendant also adduced the testimony of six other witnesses (co-workers and a waitress from the hotel lounge) that tended to impeach various aspects of the complainant’s testimony. The defendant’s wife testified in corroboration of certain aspects of the defendant’s testimony. In addition to cross-examining the complainant vigorously about, among other things, her failure to cry for help at the time of the assault and the difficulty that the defendant would have had in forcing the complainant into the car,3 defense counsel also filed requests for jury instructions that were favorable to his case on the issue of consent.
We next summarize posttrial events. After the jury found the defendant guilty, the defendant (represented by new counsel) moved for a new trial on the ground of ineffective assistance of counsel. A full evidentiary hearing was conducted, and brought out the following additional facts. Wiggins and Kelly testified, as described above, that the complainant initially claimed that she had been indecently touched, but then (on the following day) claimed that she had been raped. Kelly also testified that he twice spoke to the defendant after the complainant’s initial report, but before *269her report of actual rape. He described the conversations in the following exchange set forth below.4 Both Wiggins and Kelly testified that defendant’s trial counsel never interviewed them.
Defendant’s trial counsel testified to the following effect. During pretrial preparation of the case, he and the defendant discussed possible trial strategy on several occasions. Defense counsel initially considered producing no evidence, thus sim*270ply requiring the Commonwealth to meet its burden of proving guilt beyond a reasonable doubt. The defendant wanted to testify, however, so counsel discussed this option with him. Defense counsel concluded that the defendant appeared credible and would make a good witness before the jury. From this point, counsel and defendant discussed the two possible approaches to defense of the cases: a denial that intercourse had occurred, or an admission that it had occurred but that it had been consensual.
Before deciding to pursue consent, defense counsel discussed with the defendant the drawbacks of basing the defendant’s case on denial. It was defense counsel’s opinion that this contention would not succeed because the defendant had admitted to Kelly and Wiggins that he had intercourse with the complainant. Moreover, in the early morning hours after the incident, the defendant was seen at the Motorola offices (where he had gone after the incident so that his wife would not know that he had been with another woman). Defense counsel asked the defendant how his denial of intercourse could be reconciled with his presence at the office at a hour when he ordinarily would not be expected to be there. The defendant was unable to provide a satisfactory explanation.
Eventually, after lengthy discussion, consent was agreed on as the main defense. Evidence then was prepared by defense counsel to support this contention. Several trips were made to the hotel to search for witnesses to corroborate the defendant’s testimony. In addition to gathering evidence, defense counsel filed several pretrial motions, including motions for a bill of particulars, for discovery and inspection, for an examination of a motor vehicle, for production of the complainant’s clothing, and for a ruling on the admissibility of statements made by the complainant.
Regarding the testimony of Wiggins and Kelly, although defense counsel knew (from speaking with the defendant and through discovery materials provided by the prosecution) that the complainant had changed the story that she originally gave Wiggins and Kelly, he deliberately decided *271against calling either of them to testify. Defense counsel did so because he had been told by the defendant that, when he first spoke with Kelly, the defendant “vehemently” denied that he had anything to do with the victim on the night of the incident, but that, during the second conversation with Kelly, he reversed himself and admitted to intercourse. Defense counsel did not want the jury to learn of this contradiction. As to Wiggins (among other things), counsel was concerned about her repeating the victim’s report of rape essentially as a third fresh complaint.
Based on this testimony, the trial judge denied the defendant’s motion for a new trial. In his detailed order and memorandum (reproduced in pertinent part in the margin), the trial judge reasoned that there had been no significant breach by the defense counsel of his duty, and, even if such a breach could be assumed, no tangible harm to the defendant’s case.5
*272The defendant argues here that the judge erred in denying the motion for a new trial because defense counsel had provided ineffective assistance when he: (1) failed to interview Wiggins and Kelly, and to call them as witnesses; and (2) failed to inform the trial judge of the substance of the complainant’s original conversations with her husband, with Wiggins, and with Kelly, when the judge was considering the admissibility of the fresh complaint testimony.
For the defendant to prevail on his claim of ineffective assistance of counsel, we must conclude, first, that defense counsel’s performance fell “measurably below that which might be expected from an ordinary fallible lawyer” and, second, that the defendant’s case was prejudiced by counsel’s conduct such that the conduct “has likely deprived the defendant of an otherwise available, substantial ground of defence.” Commonwealth v. Saferian, 366 Mass. 89, 96 (1974). See Commonwealth v. Satterfield, 373 Mass. 109, 115 (1977) (requiring showing “that better work might have accomplished something material for the defense”). In cases where tactical or strategic decisions of the defendant’s counsel are at issue, we conduct our review with some deference to avoid characterizing as unreasonable a defense that was merely unsuccessful. See Commonwealth v. Rondeau, 378 Mass. 408, 413 (1979). See also Strickland v. Washington, *273466 U.S. 668, 689-690 (1984). Rather than merely unreasonable, we require that challenged tactical judgments must be “manifestly unreasonable.” Commonwealth v. Adams, 374 Mass. 722, 728 (1978). In applying this standard in this case, we have the benefit of a detailed memorandum from the trial judge. “We [will] accept [his] subsidiary findings as final if warranted by the evidence and we [will] pay substantial deference to his ultimate conclusions.” Commonwealth v. Millyan, 399 Mass. 171, 181 (1987). We consider the defendant’s arguments in light of these principles.
1. The failure to interview and call as witnesses Wiggins and Kelly. Here, we consider together what actually are two separate alleged shortcomings in defense counsel’s performance: the failure to interview Wiggins and Kelly and the failure to elicit the testimony of Wiggins and Kelly at trial. We do so because, as the Appeals Court recognized (see 28 Mass App. Ct at 421), even if it was unreasonable not to interview the two witnesses, the failure to interview them is of no import if it was not also ineffective for counsel to fail to call either of them as a witness at trial.
a. Conduct of defense counsel. Counsel decided not to use the testimony of Wiggins at trial for fear that her testimony would essentially represent a reprise of the fresh complaint testimony offered by two other witnesses. Wiggins’ testimony unavoidably would have involved repetition of the complainant’s report of rape. It was a legitimate goal of defense counsel to reduce the number of witnesses testifying to reports of rape by the complainant; therefore, the tactical decision not to call her to testify was not unreasonable.
Defense counsel decided not to offer Kelly’s testimony because he did not want the jury to learn that the defendant had told Kelly what amounted to two different stories. Because the defendant’s credibility before the jury was critical to the success of his defense, this also was a reasonable tactical decision. Defense counsel was justifiably concerned that the jury not be exposed to evidence supporting the inference that the defendant had contradicted himself in describing what had happened between him and the complainant.
*274The defendant argues that, in fact, Kelly’s testimony would not have revealed that the defendant had contradicted himself, because the defendant’s original denial was only of sexual harassment, and his subsequent admission was only of consensual intercourse. Thus, the defendant contends, if defense counsel had interviewed Kelly, he would have discovered this, and could have benefited from Kelly’s testimony without being harmed by the revelation of waffling by the defendant. This argument is unpersuasive. Defense counsel was relying on his client’s description of the conversations with Kelly in deciding whether to use Kelly’s testimony. The defendant described for counsel two conversations: the first amounting to a denial; the second amounting to an admission. Thus, the defendant in effect told defense counsel that he had contradicted himself in responding to a serious charge. The fact of that contradiction was plausibly suggestive of a guilty conscience, as well as of actual guilt. Common sense dictates that a defendant’s description of events underlying a criminal charge should be considered reliable in circumstances like this. To hold otherwise is to require both that defense attorneys assume that their clients cannot or will not assist in their own defenses, and that they investigate and confirm virtually every statement that a client makes, no matter how apparently or circumstantially accurate. Beyond being impractical, such a requirement is contrary to earlier statements on this point. See, e.g., Strickland v. Washington, supra at 691; United States v. Decoster, 624 F.2d 196, 209-210 (D.C. Cir. 1979) (S.C. 598 F.2d 311, cert, denied, 444 U.S. 944 [1979]).
The testimony of both Wiggins and Kelly would have been problematic for the defendant for another important reason. Both witnesses would testify that, although aspects of the complainant’s story had changed, she consistently reported that the defendant had forced himself upon her — that is, forcibly fondled her, as in the first report, and forcibly raped her, as in the second report. If believed, the complainant’s unwavering allegations of force obviously would have directly rebutted the defendant’s consent defense. In considering *275whether to use such testimony, defense counsel reasonably could project that a jury might forgive the complainant her hesitancy in claiming rape, but would not forget that she never abandoned her charge that the defendant dealt with her violently. In sum, defense counsel could anticipate that calling the witnesses would expose the general inconsistency in the defendant’s position and highlight the general consistency in the complainant’s testimony. In these circumstances, we are reluctant to second guess defense counsel’s considered judgment as to the value of the testimony. See 2 W.R. LaFave, Criminal Procedure § 11.10 at 47 (1990 Supp.).
(b) Prejudice. Even if we were to find that defense counsel’s conduct in not interviewing or calling to testify Wiggins and Kelly fell below that to be expected of the ordinary fallible lawyer, we would conclude that there was no resulting prejudice to the defendant’s case. Had defense counsel presented the testimony of Wiggins, he would have been able to argue that the complainant had changed her story and that these variations suggested questionable credibility. On the other hand, as noted above, Wiggins would have been an additional witness essentially testifying to a third fresh complaint, and she would also have testified that the complainant never deviated from her report that the defendant had forcibly assaulted her. Had defense counsel presented the testimony of Kelly, he could have benefited from a second witness describing the complainant’s varying story. However, again as noted above, the jury would have learned that the defendant himself had given Kelly inconsistent reports about the incident, and that the complainant consistently reported to Kelly that the defendant forcibly assaulted her.6
*276The fact that Kelly’s memory of the conversations with the defendant differed somewhat from what defense counsel understood the substance of those conversations to be does not persuade us that the failure to offer the testimony of these witnesses prejudiced the defendant’s case. This is so because, fundamentally, the conversations as Kelly remembered them paralleled counsel’s understanding of the conversations. A comparison of the two versions of the conversations is in order.
The defendant told counsel that, when Kelly called, the defendant vehemently denied having had anything to do with the complainant on the night in question. Later, however, the defendant called Kelly back and admitted to consensual intercourse. For his part, Kelly testified that the defendant at first was “shock[ed]” by the allegations; the defendant’s first response to Kelly was a denial (“No. Oh, no. No way.”); and the defendant later called Kelly back and admitted that “indeed” (i.e., as in “contrary to what was said earlier”) there had been “a situation ... that involved two consenting adults. . . .” Thus, Kelly’s description of the conversations matched that given by the defendant to counsel on the following essential points: Kelly called the defendant and leveled a charge; the defendant denied the charge; the defendant then called back and made an admission that appropriately should have been made during the first conversation. Therefore, if counsel had called Kelly to testify, the jury would have heard a description of events that basically matched the version given counsel by the defendant and that evidenced on the part of the defendant at best a sense of guilt over his relations with the complainant, and at worst a capacity for untruthfulness.
The testimony of Wiggins and Kelly had a tendency to impeach in part the complainant’s description of events. On balance, however, any benefits that the defendant would have realized from this testimony could not have risen to the level of a “substantial ground of defence” because they would have been largely offset by the harm that other aspects of the *277testimony would have done to his case. The absence of the testimony therefore was not prejudicial.
2. The failure to inform the judge of the complainant’s initial conversations with her husband, Wiggins, and Kelly when he was evaluating the fresh complaint evidence. Here, we need not undertake an extended analysis of conduct and prejudice. The judge ruled that, even if defense counsel had brought the substance of the complainant’s initial conversations with Wiggins and Kelly to his attention when he was considering the admissibility of the fresh complaint testimony, he nevertheless would have admitted the testimony. Therefore, although it would have been better if counsel had fully informed the judge, even assuming that counsel’s failure to do so was manifestly unreasonable, the outcome of the case was in no way affected.
In this case, defense counsel made difficult strategic choices based on discussion with the defendant, and after reasonable consideration of the law and the facts relating to the plausible options. Defense counsel also conducted an investigation, filed numerous pretrial motions, and vigorously represented the defendant through trial. This is not a case where defense counsel took questionable unilateral action, was excessively sloppy, gave away the defense, failed to acquaint the defendant with the main theory of his own case, or otherwise seriously bumbled a critical issue.
The trial judge’s conclusion that defense counsel was reasonably competent is supported by the evidence. Unlike this court, the trial judge had the opportunity to observe and evaluate all of the witnesses at trial, as well as defense counsel, Wiggins, and Kelly. We will not disturb his judgment.7
Judgment affirmed.
Because of the marital disqualification, G. L. c. 233, § 20, neither the complainant nor her husband was permitted to testify to the content of this conversation.
The defendant objected to the admission of this testimony on freshness grounds. The judge overruled these objections, but did so not knowing (because defense counsel did not inform him) that, prior to speaking to either of the two fresh complaint witnesses, the complainant had told her husband, Wiggins, and Kelly that she had been sexually harassed, but had averted rape.
Defense counsel effectively cross-examined the prosecution’s other witnesses as well. For example, he elicited from the forensic chemist (who examined the complainant’s panty hose) the opinion that the run in the crotch of the panty hose did not indicate tearing or excessive force. Defense counsel also brought out inconsistencies between the police officer’s testimony at trial and before the grand jury.
Q. “Now, on August 20, 1987, do you recall what time it was that you first spoke to Edward White?
A. “Mid-afternoon.
Q. “And, at that time, did you call him or did he call you?
A. “I called him.
Q. “Now, do you recall, sir, the substance of the conversation that you had with the defendant on that afternoon?
A. “Yes.
Q. “And what was that?
A. “I called him and I don’t remember the exact words, but, essentially, reported to him that there was a sexual harassment charge against him by [the complainant].
Q. “And, at that time, sir, did he indicate to you that nothing of a sexual nature had occurred between the two?
A. “No.
Q. “Do you recall what he said during that conversation?
A. “I recall, I’m not certain I have it verbatim, but I’ve gone over it many times in my mind. His reaction was shock and I remember him saying: No. Oh, no. No way. Then I proceed to describe to him some of the comments that [the complainant] had described to me, hand in blouse, hand up dress and he, I recall him saying: No way. No way. No force.
Q. “Now, at some point after that conversation that you had with the defendant, Ed White, that afternoon, did you speak to him again on the telephone that day?
A. “Yes.
Q. “And how long after the original call was that?
A. “I would guess — I was home, so, it probably was three hours.
Q. “And who made the phone call, sir?
A. “He called me.
Q. “And do you recall the substance of that conversation?
A. “Yes.
Q. “And what was that?
A. “He called and told, wanted to tell me that there was indeed a situation that happened in the parking lot at the Marriott and the situation was one that involved two consenting adults in the back seat of his automobile.”
“Failure to Call [Kelly] and Wiggins — After discussing the matter with his client, [counsel] elected not to call [Kelly] and Wiggins as witnesses at trial although their consistent testimony would have been of some value in impeaching the credibility of the complaining witness. As the defendant’s later statements to [Kelly] and his trial testimony place him inside his car having consensual intercourse with [the complainant], her initial statements are of limited impeachment value as they do not corroborate the defendant’s version. They would have been of much more significance corroborating a defense that nothing happened. [Counsel] testified that he did not call Mr. [Kelly] because there was the real danger that he would have been asked on cross-examination about the defendant’s initial denials to him. ... As to Wiggins, [counsel] was fearful that she would have disclosed that the defendant has been terminated by Motorola and that the complainant was still an employee, and the jury would have inferred that Motorola believed the complainant and not the defendant. The choice not to call [Kelly] seems to be a reasoned tactical choice by counsel. The decision as to Wiggins is not as clear because counsel could have moved in limine to ascertain whether or not the [information he was concerned about was admissible]. Nevertheless, this failure does not, in and of itself, amount to a significant error and it is most unlikely that it would have made a difference in the outcome of the case. . . .
“The Failure of Counsel to Disclose the Substance of the [Complainant’s Initial] Statements to the Court — At trial Defense Counsel objected to the admission as fresh complaint of the statement to Ms. Noguera given the same day and about 16 hours after the events. ... To assist the Court in making its determination of ‘freshness,’ it would have been preferable if either or both counsel had focused on the specifics of the disclosures to *272Wiggins and [Kelly]. In retrospect, it would have made little difference and the Court still would have admitted [the complainant’s] statement to Noguera as fresh complaint. . . .
“Assuming, without deciding, that defense counsel erred by neither interviewing nor calling [Kelly] and Wiggins, the defendant has failed in its burden to show that these decisions had a discernible effect on the outcome of the case.... Had [Kelly] testified, the jury would have learned that the defendant had admitted to intercourse, thus counsel would have been hard-pressed to create a reasonable doubt as to whether intercourse occurred.... Defendant’s trial counsel made a tactical decision after weighing the likely benefits and liabilities of two witnesses. If the jury had found a reasonable doubt, counsel would have been credited with a strategy which kept out potentially damaging evidence. A verdict to the contrary naturally calls into question all tactical decisions. The defendant has failed to show that counsel’s decisions were unreasonable, deficient, and incompetent to the extent that representation fell below that which might be expected from an ordinary fallible lawyer.” (Citations omitted.)
It is doubtful that, if Wiggins’ and Kelly’s names had appeared on the defendant’s pretrial witness list, the complainant would not have had an explanation for the shifting of her story. Obviously, a plausible explanation by the complainant as to why she waited to tell Wiggins and Kelly that she had been raped would have greatly reduced the impeachment value of their testimony, without diminishing the capacity of the testimony to damage the defendant’s case.
We see nothing in the jury instruction complained of by the defendant’s new counsel that would create a substantial risk of a miscarriage of justice.