They scored only three goals on 51 shots at goalie Carey Price and the Canadiens won the opener 4-3 on Thursday night.
On Saturday, Boston will try to gain a split of the first two games at home before the best-of-seven Eastern Conference semifinal series shifts to Montreal.
Bruins coach Claude Julien says his team remains positive and there is no panic.
And Canadiens coach Michel Therrien isn't sounding overconfident against the team that had the best regular-season record. He says the Bruins played a solid game Thursday.
Montreal won on P.K. Subban's second power-play goal of the game at 4:17 of the second overtime.