Jakub Voracek had two assists, and Giroux also had an assist to help the Flyers snap a three-game losing streak and extend their home winning streak to six games. They were coming off a 2-3-1 trip in which they finished 0-2-1, including a 7-2 loss at Chicago on Wednesday night.
"It's good to see we can put things behind us and move on," Giroux said. "Guys were pretty excited to play home again. Our fans give us a boost. That was one of our best 60-minute performances."
Mason shut out the Canadiens for 59 minutes before Alex Galchenyuk scored with 55.1 seconds left to cut it to 2-1.
The Canadiens have lost two in a row after going 9-0-1. They followed a 6-0 loss at home to the Los Angeles Kings on Tuesday with another offensive clunker.
"We were definitely slow in the first," captain Brian Gionta said. "It's tough when you start late to try and get back into the game. We made a good push, but it was just a little too late."
The Flyers didn't show any ill effects from a 13-day trip. Despite playing three games in four nights, they looked fresh from the start.
"I was happy with the way we skated," coach Craig Berube said. "You never know after a long trip how you're going to be. They were ready to go. I think there's a lot of character in the room. They weren't happy about the loss in Chicago because they wanted to show they can play with that team."
Raffl gave Philadelphia a 1-0 lead in the first period with his second NHL goal. Voracek set it up with a perfect pass from behind the net to Raffl in the slot. He wristed a shot over goalie Carey Price's glove into the top corner.
Raffl didn't score in his first 17 games, but has two goals in three games this week.
"I know when he has the puck, he's going to protect it and find me. I just have to be open," Raffl said of Voracek.
Another crisp pass from Voracek set up Philadelphia's second goal. Brayden Schenn took the puck up the middle, and he passed it to Voracek skating down the left side. Voracek sent a crossing pass to Giroux coming down the right wing, and he beat Price with a slap shot.
Danny Briere, a fan favorite during six seasons with the Flyers, returned to Philadelphia for the first time since his contract was bought out last July. Briere got a standing ovation during a video tribute in the first period and he waved to the crowd from the bench.
"It was weird playing against Danny," Giroux said. "Me and Danny are pretty close. We lived together. He's one of my good friends. But on the ice, it's a different story."
The Canadiens had a goal disallowed in the third period because Gionta pushed it in with his hand while sliding headfirst into the crease.
"I am very disappointed. Disappointing performance, honestly," Canadiens coach Michel Therrien said. "I thought especially with the game we played at home, I thought we were going to be on fire, and I am disappointed."
Mason had 10 shutouts for Columbus when he was the NHL's top rookie in the 2008-09 season, and 10 more in the last five seasons. ... The Flyers scored first for the fourth game in a row. They were 0-2-1 in the other three. ... Giroux has five goals in 13 games after getting one in the first 19. ... Canadiens D Alexei Emelin was ejected for elbowing Steve Downie late in the second period. ... Canadiens lost consecutive games in regulation for the first time since Nov. 1-2.
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