Girgensons and Grigorenko were both 2012 first-round picks by the Sabres. Both of Buffalo's 2013 first-rounders, defensemen Rasmus Ristolainen (one assist) and Nikita Zadorov, were also in the lineup for the Sabres.
"I liked a lot of our younger players and the poise that they had in an environment like this for the first time,” Sabres coach Ron Rolston said.
Jamie McBain, who arrived from Carolina in an offseason trade, and Colton Gillies, who is in camp on a tryout contract, also scored for the Sabres. Gillies tallied with 4:24 left in regulation to force overtime.
Michael Bournival scored Montreal's first two goals. Defenseman Greg Pateryn had three assists, while Jarred Tinordi had two. Michael McCarron, a first-round choice by the Canadiens in June, had an two assists and goaltender Zachary Fucale, one of Montreal's second-round selections, stopped 13 of 15 shots in relief of Peter Budaj (10 of 12). Jhonas Enroth started for Buffalo and yielded three goals on 13 shots before giving way to Matt Hackett, who turned aside 11 of 12 shots and three shootout attempts.