BOSTON -- Tuukka Rask made 25 saves, and the Boston Bruins remained undefeated under coach Bruce Cassidy with a 4-0 win against the Montreal Canadiens at TD Garden on Sunday.
Cassidy is 3-0-0 since taking over after Claude Julien was fired Tuesday.
Rask, who has six shutouts this season, 36 in his NHL career, won against the Canadiens at home for the first time in 13 regular-season games (1-9-3).
WATCH: All Canadiens vs. Bruins highlights
"I wouldn't call it a statement. I think we played a great game overall," Rask said. "It was a back-to-back for both teams, and even though they might have outplayed us just a little bit in the first (period), we still had the lead and we extended it greatly, two nice goals. So it was a great, great game."
Adam McQuaid, Zdeno Chara, David Krejci and Frank Vatrano scored for the Bruins (29-23-6), who are six points behind the Canadiens (31-19-8) for first place in the Atlantic Division.
Boston, which starts a six-day break Monday, defeated Montreal at TD Garden for the first time since Jan. 12, 2012. The Bruins were 0-7-2 in the past nine games.
Forward Brendan Gallagher returned to the Canadiens lineup after missing 18 games with a broken hand, but it didn't help their offense. After being shut out, they have scored 10 goals in their past seven games and are 1-5-1 in that span.
Carey Price made 32 saves for Montreal, which starts a five-day break Monday.
Video: Tuukka Rask earns Sunday's Pepsi Zero Sugar Shutout
"I thought tonight, the first period we were really intense, we got some quality chances," Canadiens coach Michel Therrien said. "We just lost momentum in the second with the special teams, they scored on their power play, and when we were on our power play, we got scored [on]. So they were up by three goals, and that was it."
McQuaid scored his second goal of the season at 8:57 to give the Bruins a 1-0 lead.
The Bruins killed a 5-on-3 power play for the Canadiens that lasted 1:37 to carry the one-goal lead into the first intermission.
Chara scored the seventh shorthanded goal of his NHL career, first since Jan. 1, 2011, at 5:08 of the second period for a 2-0 Boston lead. Krejci scored a power-play goal at 15:05 to make it 3-0.
Vatrano scored at 5:00 of the third period for a 4-0 lead.
Video: MTL@BOS: Krejci finishes tic-tac-toe play for PPG
Goal of the game
Rookie forward Peter Cehlarik made a cross-ice pass out of the right corner, and McQuaid beat Price with a one-timer after a backdoor cut.
Video: MTL@BOS: McQuaid buries a one-timer from Cehlarik
Save of the game
During the 5-on-3 penalty kill in the first period, Rask made a right-pad save on a Max Pacioretty slap shot from above the right faceoff dot at 16:08.
Highlight of the game
Chara scored from the right hash marks at 5:08 of the second period. The Bruins defenseman skated around Canadiens forward Alexander Radulov before beating Price with a wrist shot.
Video: MTL@BOS: Chara buries top-shelf SHG from the slot
Unsung performance of the game
It's been a regular occurrence this season for Chara to play the entirety of 5-on-3 penalty kills, and he did it again for 1:37 in the first period. He had 7:37 of shorthanded ice time to help the Bruins go 6-for-6 on the penalty kill.
They said it
"We just seem to have lost our identity. We're a little loose. We just have to take a step back and get refocused." -- Canadiens goaltender Carey Price
Video: MTL@BOS: Price stones Pastrnak on the doorstep in 2nd
"I think it's a level of intensity that's gone up, a level of commitment that's gone up, a level of execution that's gone up and a level of belief. It seems like a different team when we're out there even when we get scored on. Our Achilles heel prior was that the next couple minutes were a continued lull. Tonight, obviously we don't get scored on, but the mentality that we go out there with, believing that we're going to win and the guys really are starting to buy in to the little things that it takes to win games. You look at the penalty kill and how that's performing, and that's a great place to start." -- Bruins forward David Backes on their improved play
Need to know
Rask passed Frank Brimsek for second place on Boston's all-time shutouts list. ... McQuaid played his 400th NHL game, and Gallagher and Bruins forward Riley Nash each played his 300th. ... Cehlarik had two assists for his first two NHL points. … Boston matched its season high with its third win in a row.
Canadiens: Host the Winnipeg Jets on Saturday (2 p.m. ET; CBC, SN, TVA Sports, NHL.TV)
Bruins: At the San Jose Sharks on Sunday (8:30 p.m. ET; NBCSN, NHL.TV)
Video: Rask, Bruins blank Canadiens, 4-0