Sean Monahan's second goal of the game 1:14 into overtime gave the Calgary Flames a 3-2 victory over the Montreal Canadiens on Thursday night.
Monahan finished a 2-on-1 break by taking a feed from Johnny Gaudreau and beating Carey Price from the slot.
David Rittich got only his second career start in goal for Calgary and made 35 saves, while Price stopped 34.
Garnet Hathaway also scored for Calgary (14-12-2), which was coming off a shootout loss in Toronto on Wednesday night.
Daniel Carr and Phillip Danault scored for Montreal (13-13-4).
Each team scored from the side of the net in the first frame. Monahan's first shot hit the side, but he picked up the rebound, spun around and sneaked the puck inside the near post at 6:31. Then Carr backhanded a shot in off Rittich's back from close range at 8:36.
It was the sixth point in four games for Carr since he was called up from AHL Laval last week.
Max Pacioretty broke down the right side and backhanded a pass in front that Danault tipped over Rittich's glove at 10:10 of the second period.
The Flames got the puck into the net in a goal-mouth scramble at 7:49 of the third, but officials ruled no goal because Price was pushed into the net. Calgary challenged, and the second review showed no interference and the goal was awarded to Hathaway -- his first of the season and second in 46 NHL games.
Hathaway, Sam Bennett and Brett Kulak were jamming at the puck when it crossed the line.
The Flames had a chance for the lead with a two-man advantage for a full minute starting at the 12:47 mark but couldn't score.
With Matthew Tkachuk's one-game suspension, Freddie Hamilton moved into the Calgary lineup. Curtis Lazar played his 200th game. Jaromir Jagr sat out a second straight game with a lower-body injury.
Montreal started Jakub Jerabek on defence, bumping Victor Mete. Jonathan Drouin skated Thursday morning but still missed a fourth game, the last two with an illness.