Ryan Spooner scored in overtime as the visiting Boston Bruins beat the Montreal Canadiens 2-1 on Monday night.
Austin Czarnik scored for the Bruins (16-12-2) in regulation time. Tuukka Rask made 29 saves for the win as Boston handed Montreal a rare home loss.
Paul Byron scored late in the third period to salvage a point for Montreal (19-6-4). Carey Price stopped 26-of-28 shots in defeat, just his fifth loss of the season.
David Krejci looked to have given the Bruins the victory the victory 59 seconds into overtime but referees determined David Pastrnak had interfered with Price, preventing him from making the save.
Spooner made it official with 1:40 remaining in overtime, beating Price on a partial breakaway.
The Canadiens challenged the goal, claiming Spooner was offside on the play, but the goal stood.
The loss was only Montreal's third at the Bell Centre this year (14-1-2).
The Canadiens and Bruins have a stormy history and it didn't take long for the bad blood to spill over between two of hockey's greatest rivals.
Alexei Emelin set the tone for the encounter 13 minutes in with a big shoulder-to-shoulder bodycheck along the boards on young Bruins phenom Pastrnak.
Torey Krug answered seconds later with an elbow to the head on Andrew Shaw in open ice in the neutral zone. The Habs winger went straight to the dressing room but was back for the start of the second period.
There was no penalty on Krug on the play.
Brendan Gallagher took matters into his own hands, dropping the gloves with Krug with five minutes remaining in the first.
The second period saw fewer dust-ups, and was more about Price and Rask repeatedly frustrating their opponents.
Price denied Czarnik on a partial break early in the frame. The Canadiens netminder then made a big pad save on Patrice Bergeron later on in the period.
Rask's biggest stop in the second was when he went down and stacked the pads on Tomas Plekanec, just seconds after Pastrnak hit the post at the other end of the rink.
Czarnik broke the deadlock with 1:05 remaining in the middle frame.
The 24-year-old beat Price for his third goal of the season as he fired a shot between Price's pad and blocker while on a 2-on-1.
Nathan Beaulieu was the lone defenceman back, but his sliding effort just missed Czarnik's shot.
Rask kept his shutout bid alive until 16:48 of the third period when Byron scored on Montreal's 29th shot on goal.
After a scramble in front of Rask's net, the Bruins goalie lost track of the puck as Byron backhanded home his 10th of the campaign.
Notes: Price was denied his 250th NHL win. Rask is now 6-15-3 in his career versus the Canadiens. Pastrnak leads the Bruins with 18 goals.