BOSTON — Brad Marchand waited patiently along the boards, sizing up the situation before swooping around the net and finding his spot to shoot.

Marchand scored 2:06 into overtime to lift the Boston Bruins to a 2-1 comeback win over the Canadiens on Saturday.

“You’re just looking for an opening, that’s kind of how it was,” he said. “You could tell they were a little tired. You’re kind of just waiting for that opening to show itself and luckily it did.”

It was the Bruins’ third straight victory and completed their four-game sweep of the season series with their archrivals for the first time since 1994-95.

“To have the puck that long and score — heck of a goal,” Boston coach Bruce Cassidy said.

Marchand’s score came on the Bruins’ 50th shot on goal.

Boston defenseman Charlie McAvoy suffered what the club called “a lower-body injury” on the game’s opening shift. It only took a few minutes for the team to announce that he was “not likely” to return, and it gave no further information.

“All I did, was see it real quick on the bench,” Cassidy said. “Did he get his foot caught up with the other guy? Or is that something before that? I don’t have a good answer for that to be honest. … Hopefully it’s not serious. It didn’t look serious at the time.”

Boston was coming off an eight-goal game — its highest total since 2012 — in a win over Pittsburgh on Thursday. The Bruins didn’t score Saturday until Jake DeBrusk’s tying goal with 2:45 left in regulation.

With Boston in danger of being shut out for the second time this season, DeBrusk tipped Nick Holden’s shot past Antti Niemi after center Jonathan Drouin was sent off for a delay-of-game penalty.

“When you take six penalties whether deserved or whatever the case may be, eventually it catches up to you,” Montreal coach Claude Julien said.

Boston scored the tying goal on its sixth power play.

“We’ve been through it so many times this year and different guys have stepped up numerous times,” Marchand said. “We know we have a lot of character and can rely on different guys every night.”

Anton Khudobin made 27 saves for Boston.

Brendan Gallagher scored and Niemi made 48 saves for the Canadiens.

“He definitely did his job and gave us a chance to win,” defenseman Jeff Petry said of Niemi.

Gallagher gave Montreal the lead when he stole a puck from defenseman Kevan Miller near the blue, skated into the slot and beat Khudobin with a wrist shot inside the left post 9:16 into the game.

The Bruins tied their season high for a period with 19 shots on goal in the second – and even had a two-man power play for 41 seconds – but Niemi had solid positioning and controlled the rebounds.

Khudobin had the better highlight saves, though. His best was a sprawling right-pad stop with his legs completely split on Logan Shaw’s shot from the edge of the crease.

Boston forward David Pastrnak missed an excellent opportunity when he hit the left post at the end of a 3-on-1 break six minutes into the game.

Follow BDN Maine Sports on Facebook for the latest in Maine high school and college sports.