Ordered that the order is affirmed insofar as appealed from, with costs.
A party seeking to vacate an order entered upon default is required to demonstrate both a reasonable excuse for the default, and the existence of a meritorious cause of action or defense ( see CPLR 5015 [a] [1]; Henry v. Kuveke, 9 AD3d 476; Weekes v. Karayianakis, 304 AD2d 561; Parker v. City of New York, 272 AD2d 310). The determination of what constitutes a reasonable excuse for a default lies within the sound discretion of the Supreme Court ( see London v. Iceland Inc., 306 AD2d 517; J.P. Equip. Rental Materials v. Fidelity Guar. Ins. Co., 288 AD2d 187; Parker v. City of New York, supra). Contrary to the defendant's contention, the Supreme Court providently exercised its discretion in finding that the plaintiff provided a reasonable explanation for his default in opposing two motions ( see Miller v. Doniger, 256 AD2d 244; Wilson v. Misericordia Hosp., 244 AD2d 163; McNeil v. Milstein, 240 AD2d 549; Lanc v. Donnelly, 184 AD2d 840; see also Russo v. Russo, 289 AD2d 467; Parisi v. McElhatton, 209 AD2d 495). Furthermore, the plaintiff's submissions were sufficient to demonstrate the existence of a potentially meritorious cause of action.