David Rittich got his first start of the season, Jacob Markstrom serving as the backup after playing the Flames first five games. He made 17 saves on the night.
After Tuesday's 4-3 loss to the Maple Leafs where the Flames were outshot 10-1 and trailed 2-0 after the opening 20 minutes, the team - to a man - were all singing from the same song sheet: They had to be better in the first period and show up 'on time.'
Mission accomplished, as they played with pace early, generating a few good chances in the opening minutes - including one by Andrew Mangiapane that Carey Price kicked out a pad to stop.
Juuso Valimaki was called for a hook at 8:13, putting the spotlight on Calgary's PK, which was ranked 12th coming into the tilt.
They were aggressive early and kept the Habs from getting set up, but near the end of the advantage, Corey Perry got the puck down low beside the net and made a no-look backhand pass to Brendan Gallagher, who scored his third of the season.
The Flames next great crack came courtesy of Josh Leivo, who sent a cross-ice pass to Elias Lindholm on the backdoor but he wasn't able to get all of the bouncing puck and missed wide.
Later in the shift, Lindholm was whistled for hooking Jonathan Drouin, sending Montreal back to the PP.
They made good again.
Canadiens captain Shea Weber scored, stepping into a slapshot from the flank that deflected off the stick of Valimaki and went high, shortside past Rittich.
Johnny Gaudreau - who had two goals in the Flames 4-3 loss to Toronto on Tuesday and came into the tilt leading Calgary with four tallies this season - rang one off the bar from a tight angle before the period ended, inches away from putting the visitors on the board.
Big Save Dave reminded everyone why he has that moniker, coming across to stop two great shots from Gallagher six minutes into the second period.
The Canadiens made it 3-0 at 8:21 off a 2-on-1 rush, Rittich stopping Jesperi Kotkaniemi's shot but Josh Anderson whacking the rebound out of the air into the wide-open net.
Tyler Toffoli - the Canadiens leading scorer - made it 4-0 with a shorthanded marker, his sixth of the season, in the final minute of the second, scoring on a breakaway by somehow getting a bouncing puck under Rittich.
The Flames got a pair late in the third when Sam Bennett's shot was tipped by Milan Lucic. Montreal challenged saying the play was offside, but after review the officials disagreed.
