MONTREAL (AP) -- The Montreal Canadiens couldn't help but feel a sense of payback.
The Canadiens had been seeking to get even with the Senators since last spring when Ottawa eliminated them in the opening round of the playoffs.
Montreal got a small measure of that Friday night as they defeated the Senators 7-4, making Ottawa's chance at returning to the postseason more difficult. The Senators remained seven points out of the final wild-card berth in the East with just five games remaining.
Max Pacioretty had a hat trick as the Canadiens scored seven straight after falling behind 3-0.
"This year we definitely felt like we owed them a little payback for last year in the playoffs and our games have been heated against them," Pacioretty said. "It's not just on the scoreboard that feels good it's seeing guys step up and stand up for their teammates. I think that's one of the more rewarding feelings about the night."
Andrei Markov, Mike Weaver, Lars Eller and David Desharnais also scored for Montreal as Peter Budaj stopped 39 shots for his 10th win of the season.
Zack Smith scored twice for the Senators while Ales Hemsky and Mika Zibanejad had the other goals. Craig Anderson stopped 17 shots.
Ottawa jumped out to a 3-0 lead before the game was 6 minutes old, but then allowed the Canadiens to steamroll past.
"It's hard to pinpoint exactly what happened," Smith said. "We lost control of the game. We were up three goals and it didn't take them long to get those back and after that it was hard to get any traction. A couple of soft plays and turnovers and they're in our net."
Smith had few answers as to why or how the Senators could crash so badly, but admitted it wasn't pretty.
"We say playing Montreal it's an easy game to get up for," he said. "That's embarrassing. We're up 3-0 and they score seven straight."
Senators coach Paul MacLean was at a loss for words.
"I'm numb," he said. "We came out and played and got the lead 3-0 and then we stopped playing. We stopped doing the things that made us successful."
With already two on the night, Pacioretty completed his hat trick at 1:09 of the third and Desharnais made it 7-3 midway through the third beating Anderson up high.
The Senators got on the board again with 5:53 remaining as Zibanejad beat Budaj.
Despite being outshot 15-4 in the second the Canadiens scored twice to take a 5-3 lead after 40 minutes.
"Obviously you look at the shots and we got some favourable bounces and that's just the way it goes some nights," said Pacioretty. "It just shows our last two games against them you're never down and out."
Montreal took its first lead of the game as Eller jumped on a rebound early in the second to make it 4-3.
Ottawa appeared to tie it up on the ensuing play, but the goal was disallowed due to incidental contact on the goaltender.
The call left the Senators extremely frustrated as they felt video review clearly showed there was no contact by an Ottawa player on the play.
Montreal made it 5-3 on Pacioretty's second of the night as he took advantage of a Senators turnover and broke in alone to beat Anderson through the legs.
The game was made that much more interesting after Erik Karlsson checked Brendan Gallagher hard into the boards and Alex Galchenyuk took offense, leading to Karlsson and Galchenyuk exchanging a couple of punches.
Trailing 3-0 the Canadiens got on the board as Markov scored off a bad angle down low on Montreal's second shot of the game. Two minutes later Weaver's point shot made it past a screened Anderson.
Montreal tied it as Pacioretty got past Ottawa's Eric Gryba on a bouncing puck and beat Anderson between the legs.
"It's brutal," MacLean said. "We're at home and we stopped playing. It's not right."
After giving up the early lead, Montreal's P.K. Subban saw just 37 seconds of ice time in the first and didn't get another shift until the Canadiens went on the power play at the two-minute mark of the second.
Ottawa opened the scoring two minutes into the first as Smith scored his first off his backhand.
The Senators made it 2-0 just over two minutes later as Hemsky tipped Patrick Wiercioch's point shot, and it was 3-0 as Smith scored his second of the game off a great pass from Zibanejad.