After all the heavy hitting, Boston's Ryan Spooner got the final blow.
Spooner scored in overtime and his goal withstood a video review, lifting the Bruins over the Canadiens 2-1.
Spooner got his goal 3:20 into OT on a partial breakaway off a nice give-and-go with Torey Krug. Montreal challenged, claiming Spooner was offside, but the goal stood.
That ended a rough-and-tumble game between franchises that first met in 1924.
''You saw a lot of hitting tonight,'' Bruins coach Claude Julien said. ''A lot of borderline hits, something we hadn't seen between these two teams for a while. The fans seemed to love it.
''We'll try to keep within the rules and continue to make some exciting games between the two teams.''
It didn't take long for the bad blood to spill over between the rivals.
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.
''It was a good hit,'' Julien said.
Montreal's Brendan Gallagher disagreed. Gallagher took matters into his own hands, dropping the gloves with Krug with five minutes remaining in the first.
''When you see your teammate get up the way Shaw did, he had blood coming from his face, Shaw would have done that for every guy on this team,'' Gallagher said. ''It's tough whenever you play this team. A lot of emotions involved.''
David Krejci appeared to give the Bruins a victory 59 seconds into overtime, but officials determined Pastrnak had interfered with Price.
The loss was only Montreal's third at the Bell Centre this year (14-1-2).
The second period featured 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 when he fired a shot between Price's pad and blocker while on a 2-on-1. Nathan Beaulieu was the lone defenseman back, but his sliding effort just missed Czarnik's shot.
''The last time I went up high and he got it with his stick,'' Czarnik said. ''So I figured I would just shoot it low, just get it on net and create something and it went in.''
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 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.
Bruins: Play at Pittsburgh on Wednesday night.
Canadiens: Host San Jose on Friday night.
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