Ordered that the order is affirmed, with costs.
To vacate their default, the defendants were required to demonstrate a reasonable excuse for the default and the existence of a meritorious defense ( see CPLR 5015 [a] [1]; Santiago v. New York City Health Hosps. Corp., 10 AD3d 393; Spells v. AP Supermarkets, 253 AD2d 422; Roussodimou v. Zafiriadis, 238 AD2d 568, 568-569). The determination of what constitutes a reasonable excuse for a default lies within the sound discretion of the Supreme Court ( see Carnazza v. Shoprite of Staten Is., 12 AD3d 393; Roussodimou v. Zafiriadis, supra at 569). The Supreme Court providently exercised its discretion in finding that the defendants presented a reasonable excuse for their default based on the mental condition of their former counsel ( see State of New York v. Kama, 267 AD2d 224; Price v. Salvo, 203 AD2d 349; Knight v. City of New York, 193 AD2d 720, 722; Bazzini v. Hertz Corp., 183 AD2d 691; Chery v. Anthony, 156 AD2d 414, 416; Berman v. Brunswick Hosp. Ctr., 94 AD2d 736; Hargett v. Health Hosps. Corp. of City of N.Y., 88 AD2d 633). Furthermore, the defendants' submissions were sufficient to demonstrate the existence of a potentially meritorious defense.