Dissenting Opinion by
Hoffman, J.:I cannot agree with the Majority’s conclusion that the trial court abused its discretion in failing to grant appellant’s petition to open judgment. I agree that appellant’s petition was promptly filed and that a meri*371torious defense was averred. I fail to see, however, why the lower court’s finding that appellant did not justify' its failure to answer appellee’s complaint amounts to an abuse of discretion.
As the Majority notes, a lower court’s disposition of a petition to open judgment is a matter of discretion, and will not be overturned in the absence of a clear, manifest abuse of that discretion. Pappas v. Stefan, 451 Pa. 354, 304 A.2d 143 (1973); Balk v. Ford Motor Co., 446 Pa. 137, 285 A.2d 128 (1971). While lip-service is often paid to that term, it is rarely defined. It is necessary that we state exactly what we mean when we refer to an “abuse of discretion”: “When the court has come to a conclusion by the exercise of its discretion, the party complaining of it on appeal has a heavy burden; it is not sufficient to persuade the appellate court that it might have reached a different conclusion if, in the first place, charged with the duty imposed on the court below; it is necessary to go further and show an abuse of the discretionary power. ‘An abuse of discretion is not merely an error of judgment, but if in reaching a conclusion the law is overridden or misapplied, or the judgment exercised is manifestly unreasonable, or the result of partiality, prejudice, bias or ill-will, as shown by the evidence or the record, discretion is abused.’ Mielcuszny et ux. v. Rosol, 317 Pa. 91, 93, 94, 176 A. 236.” Garrett’s Estate, 335 Pa. 287, 292-93, 6 A.2d 858 (1939). (Emphasis added). See also Mackarus Estate, 431 Pa. 585, 246 A.2d 661 (1968).
I respectfully submit that the Majority opinion fails to adhere to the proper standard of review an appellate court must employ when passing on a discretionary decision of a lower court. The Majority opinion is couched in language which does no more than indicate that the Majority, were it deciding the petition de novo, would have reached a different result: “We are, however, convinced that the appellant has reasonably explained the default and so the default judgment should have been *372opened.” (Emphasis added). Further, the Majority notes that “[o]ur court has held that where failure to answer was due to an oversight, an unintentional omission to act, or a mistake of the rights and duties of the appellant, the default judgment may be opened.” (Emphasis added). The Majority opinion, however, fails to explain why the lower court abused its discretion. The very language used by the Majority indicates that the lower court applied the proper legal principles, but that the Majority and the trial judge differ as to the effect of those principles on the facts of this case. As pointed out by Judge Jacobs, dissenting in Sta-Rite Industries, Inc., Water King Division v. Century Water Treating and Grace M. Lehman, 230 Pa. Superior Ct. 285, 326 A. 2d 425 (1974), it is one thing to hold that the lower court’s decision to open a default judgment is a proper exercise of discretion, but quite a different matter to hold that the court abused its discretion because it denied a petition to open judgment.
I agree with the Majority that the appellant’s failure to file an answer or enter an appearance was the result of negligence, rather than the product of a deliberate attempt to delay. The Majority cites three decisions for the proposition that in this situation “the default judgment may be opened.” Two of these cases affirmed the rulings of the lower court which opened a default judgment. Balk v. Ford Motor Co., supra; Samuel Jacobs Distributors, Inc. v. Conditioned Air, Inc., 223 Pa. Superior Ct. 466, 301 A. 2d 907 (1973). Thus, these cases do not stand for the proposition that a denial of a petition to open is an abuse of discretion in a case where the defendant’s failure to answer was caused by an oversight or an unintentional omission. See also Johnson v. Yellow Cab Co. of Philadelphia, 226 Pa. Superior Ct. 270, 307 A. 2d 423 (1973).
The third case cited by the Majority, Fox v. Mellon, 438 Pa. 364, 264 A. 2d 623 (1970), did reverse the lower *373court’s denial of the petition to open. In Fox, the default judgment was entered on the first day after the appellant’s twenty-day period in which to file an answer or enter an appearance had expired. The Court was concerned that “. . . this was a studied attempt by appellee to obtain a default judgment.” 438 Pa. at 367, 264 A. 2d at 625. In the present case, however, the default judgment was not entered until nine days after the twenty-day period had elapsed.
It must be remembered that “[a] petition to open judgment is addressed to the sound discretion of the court and is an appeal to the court’s equitable powers.” Wenger v. Ziegler, 424 Pa. 268, 273, 226 A. 2d 653, 655 (1967). See also Atlas Aluminum Corp. v. Methods Research Products Company, 420 Pa. 407, 218 A. 2d 244 (1966). In passing on a petition to open judgment, the trial court’s decision is basically an equitable determination made under all the circumstances. We should not reverse a decision of this kind absent a showing by the appellant that the trial court committed a clear and manifest abuse of discretion. It is not enough that we would decide differently were we the court of initial jurisdiction. There must be a demonstration that the trial court applied erroneous legal principles to the factual situation presented, or that the court was biased or prejudiced against the appellant. This is clearly not such a case.
I would affirm the order of the court below.
Jacobs and Spaeth, JJ., join in this dissenting opinion.