CALGARY -- Sean Monahan scored 2:26 into overtime to give the Calgary Flames a 4-3 win against the Buffalo Sabres at Scotiabank Saddledome on Tuesday.
Michael Frolik, Micheal Ferland and Matthew Tkachuk also scored, and Chad Johnson made 18 saves in the Flames' first win of the season.
"When you win it brings confidence," Monahan said. "As a group, it's home ice, and the way that we battled back and found a way to win is big for our team."
Zemgus Girgensons, Ryan O'Reilly and Marcus Foligno scored for the Sabres, and Robin Lehner made 30 saves.
"I don't think there's many positives to take at all," O'Reilly said. "Our compete level, our execution, was just embarrassing. That's not the way we want to be. We want to be a consistent team. We have to be a lot better."
Video: BUF@CGY: O'Reilly puts the Sabres back on top
Monahan took a pass from Johnny Gaudreau in the slot and lifted a shot over Lehner's blocker for the winner.
"I just tried to get open," Monahan said. "Johnny had the puck. When he has the puck you try to find a soft spot. He threw a saucer on my stick. It was a great play there by Johnny."
The win was Glen Gulutzan's first with the Flames. He was hired June 17 to replace Bob Hartley.
"I was more excited for the guys," Gulutzan said. "You get to be around your team for a month here and we've got a great group and they're trying. They're really putting it out there. They're squeezing a little bit. To get that off them, I think, will move us forward. So we needed it and they needed it."
Girgensons scored 7:25 into the first period, and Frolik tied the game at 16:12.
O'Reilly put the Sabres up 2-1 with a power-play goal at 11:41. Johnson stopped his one-timer, but the rebound ricocheted off Flames defenseman Dougie Hamilton and into the net.
Ferland tied the game 2-2 at 1:10 of the third, and Foligno restored Buffalo's one-goal lead with a shot over Johnson's glove at 3:49. But Tkachuk tied the game 3-3 with his first NHL goal at 4:52.
"Obviously unbelievable," said Tkachuk, the No. 6 pick in the 2016 NHL Draft. "You dream about scoring in the NHL for a long time. Now that I've got the first one out of the way, hopefully we can just keep rolling as a team and keep putting the puck in the back of the net like we did tonight."
Video: BUF@CGY: Tkachuk ties game with first NHL goal
Goal of the game
Foligno took a pass from Brian Gionta and darted by Calgary defenseman Deryk Engelland before shooting over Johnson's glove to put the Sabres up 3-2 at 3:49 of the third.
Video: BUF@CGY: Foligno eludes defenders, scores on wrister
Save of the game
Johnson stopped Sam Reinhart with 3:03 remaining in regulation, sliding over to stop the Sabres forward after he took a pass from O'Reilly. O'Reilly initially forced a turnover from Ferland at the Flames blue line to set up the 2-on-1 chance.
Video: BUF@CGY: Johnson moves to his left to deny Reinhart
Unsung moment of the game
Johnson made two saves off O'Reilly in alone on the first shift of overtime. O'Reilly beat two Flames defenders in the corner before skating out and getting two chances from six feet on Johnson. "He's confident in his crease," Monahan said. "He's moving the puck well and made some huge saves and kept us in the game."
Video: BUF@CGY: Johnson keeps Flames alive with great stops
Highlight of the game
Monahan lifted a shot over Lehner's blocker at 2:26 of overtime.
Video: BUF@CGY: Monahan wins game with point-blank wrister
They said it
"We knew that you can't change what happened in the past. (Matt Stajan) said it before this game started, 'Let's try to get three (wins) heading into Chicago.' That's something I had in the back of my head throughout the whole game and I'm sure a few other guys did. We want to change the momentum of the first start of the year with the next couple of games." - Flames forward Matthew Tkachuk
"Definitely the feeling in this room is we expect to win every night and it has to start with wins. It's a frustrating game. We had a few leads and to blow them or just to give them up, it's tough, but it's the way the game goes." -Sabres forward Marcus Foligno
Need to know
Sabres equipment manager Robert 'Rip' Simonick worked his 3,500th NHL game Tuesday. Forward Nicholas Baptiste made his NHL debut against the Flames. Johnson, who made his second consecutive start for Calgary, won 22 games and had a 2.36 goals-against average in 45 games for Buffalo last season. Brett Kulak earned an assist on Frolik's goal for his first NHL point.
Sabres: At the Vancouver Canucks on Thursday (10 p.m. ET; SN360, MSG-B, NHL.TV).
Flames: Home against the Carolina Hurricanes on Thursday (9 p.m. ET; SNF, FS-CR, NHL.TV).
Video: Monahan scores in overtime to give Flames a 4-3 win