Charlie McAvoy had three assists, Fraser Minten had a goal and an assist, and Jeremy Swayman made 22 saves for Boston (30-20-2), which has won consecutive games, and eight of nine.
Cole Caufield scored his second NHL hat trick, Nick Suzuki had two assists, and Sam Montembeault made 17 saves for Montreal (28-17-7), which has lost consecutive games.
The Bruins scored twice in 12 seconds in the third period to take the 4-3 lead.
Minten scored at 13:55 to tie it 3-3, scoring on a backhand from the slot after his shot attempt bounced back to him off Canadiens defenseman Alexandre Carrier.
Geekie scored 12 seconds later to put the Bruins up 4-3 at 14:07. He scored his second goal of the game, his 100th in the NHL and Boston’s third on the power play, on a one-timer from the point.
Caufield, who gave the Canadiens three one-goal leads, has 10 points (eight goals, two assists) during his third five-game goal streak in the NHL. His first three-goal game was on April 29, 2022, in a 10-2 win against the Florida Panthers.
Caufield scored at 6:36 of the first period to put the Canadiens up 1-0. He sped between Jonathan Aspirot and Elias Lindholm to score stick side from the slot on a flip pass from Mike Matheson, who held up to draw defenders after carrying the puck up the middle.
Viktor Arvidsson tied it 1-1 with a power-play goal at 1:45 of the second period. He put away his own rebound from the right side of the goalmouth after Montembeault stuck out his left pad to stop Arvidsson’s first shot on a backdoor pass from Minten.
Caufield got his second goal of the game on a power play at 7:37 to give Montreal a 2-1 lead, scoring on a one-timer from the bottom of the left face-off circle.
Geekie tied it 2-2 at 9:46 with Boston’s second straight power-play goal. He shot into a wide-open net from the left edge of the crease on a pass from David Pastrnak.
Caufield made it 3-2 at 13:29 with his second straight power-play goal, exploiting a small opening over Swayman’s right shoulder with a precise shot from an even tighter angle than his previous goal.
