OTTAWA -- As the Montreal Canadiens continue to climb, the Ottawa Senators' freefall doesn't seem to have an end in sight.
Even though the Habs were the visitors at Scotiabank Place, the large contingent of their supporters cheered and sang all night long, drowning out the home fans on the few occasions they had something to get excited about.
Chris Kelly had the only goal for the Senators (17-25-7), who have lost six straight on home ice.
"I can't explain it," said Senators captain Daniel Alfredsson, at a loss to explain his team's predicament. "We're not making good decisions with (the puck) and part of it because we don't want to make mistakes.
"We try to make plays we normally wouldn't and instead of just making the open play we're complicating things and it's costing us."
The start of the third period summed up the Senators' difficulties this season. Trailing 5-1, they had a two-man advantage for 1:10 to try to make the score respectable.
Not only did Ottawa manage just three weak shots, but moments after the penalties expired, Kostitsyn scored to give the Canadiens a 6-1 lead. Subban completed the onslaught with a power-play goal at 12:43.
The Senators have lost five straight and 11 of their last 12, scoring just 14 times in those 11 losses.
"We put ourselves in this position and we're going to keep working and try to turn things around," Alfredsson added.
The Canadiens, meanwhile, regrouped from a 2-1 overtime loss in Buffalo on Tuesday and have seven wins in their past 10.
Pouliot and Plekanec gave the Canadiens a 2-0 lead fewer than four minutes into the game. Kelly cut that lead in half with a goal midway through the period to make it 2-1 after the first.
The Canadiens put the game out of reach in the second, capitalizing on Ottawa mistakes that have become all too familiar this season.
Montreal struck early the period as Gionta scored at 1:12 before Pacioretty increased the lead to 4-1 with a power-play goal at 5:37.
"You could see when they scored their goal that they were working to get back into the game," Pouliot said.
"They weren't playing bad but when we got those two quick goals in the second it just knocked them down. After that we just took control of the game and did our job. Everyone contributed to this win."
Pacioretty's goal sent Senators starter Mike Brodeur to the bench after allowing four goals on just 15 shots.
Brian Elliott took over and surrendered the fifth Canadiens' goal on just the second shot he faced as Plekanec scored on a breakaway. He finished with 17 saves.
Carey Price made 33 saves for the Canadiens.
"In the first period I was just trying to give our guys a chance to win and they did the rest. After we popped in a few it was just maintenance control really," Price said, adding he felt for the Senators, who fell 6-2 in Philadelphia on Thursday night.
"I've been on the other side of the spectrum and it's not fun. You just have to battle through it, put it behind you and look to the next game. It's all you can do really."
The Senators are off until Tuesday when they host the Buffalo Sabres. The Canadiens, meanwhile, host the Anaheim Ducks at the Bell Centre on Saturday in former captain Saku Koivu's return to Montreal.
Notes: Senators defenceman Brian Lee played in his 100th NHL game. ... Alex Kovalev was back in the lineup for the Senators after missing six games with a knee injury. Matt Carkner and Jarkko Ruutu both missed the game with lower body injuries. ... Senators F Milan Michalek is tied for the league lead with three short-handed goals. ... Canadiens D Hall Gill played his 102-consecutive game and is the Canadiens' current iron man. ... The Canadiens were without the services of Mike Cammalleri after he suffered a shoulder injury Tuesday. ... Canadiens captain Brian Gionta hasn't registered an assist in 20 straight game. He has just seven goals during that stretch. ... Attendance was 20,337.