Tim Thomas made 32 saves as the Bruins bounced back from two straight home losses to cut their deficit to 2-1 in their Eastern Conference quarterfinal series against the Habs.
Boston got first-period goals from David Krejci and Nathan Horton and an empty-netter from Chris Kelly. Bruins defenseman Zdeno Chara, who missed Game 2 after being hospitalized with dehydration, returned to notch an assist.
Montreal got goals from Tomas Plekanec and Andrei Kostitsyn. Canadiens netminder Carey Price, who had turned aside 65 shots in the first two games, yielded three goals on 24 shots.
Game 4 will be Thursday in Montreal.