CALGARY — There was a palpable sense of relief in the Calgary Flames' locker-room after Sean Monahan's overtime winner on Tuesday.

Monahan's second goal of the year 2:26 into overtime gave Calgary a 4-3 victory over the Buffalo Sabres, the Flames first of the season. The 22-year-old made a nifty move and neatly beat Sabres goalie Robin Lehner over his shoulder after being set up alone in front by Johnny Gaudreau.

"Everybody needed that goal and when I say everybody, probably the fans, the coaches and Mony himself," said Glen Gulutzan, who earns his first victory as Calgary's coach.

In dropping back-to-back games in Edmonton and then losing in overtime in Vancouver on Saturday, pressure was already building on a team expected to take a giant step forward in 2016-17.

"When you win, it brings confidence," said Monahan. "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."

Much of the scrutiny has been on Monahan and Gaudreau, both fresh off signing lucrative long-term contracts in the off-season. Coming into Tuesday, Monahan had one goal, Gaudreau one assist and they were a combined minus-7.

"Making that big play. Hopefully it's the beginning of them getting their game going again," said Gulutzan. "I know both young guys have been putting pressure on themselves and I can see it. It just takes one of those things to turn it when you're the quality of player of both of those gentlemen."

Monahan said that his linemate deserves most of the credit for his game-winning goal.

"Johnny had the puck and when he has the puck you try to find a soft spot. He threw a sauce on my stick," said Monahan, who missed most of training camp as well as the World Cup with a strained back..

Calgary trailed 2-1 entering the third period but tied it when Micheal Ferland scored on a nice backhander of a giveaway by Marcus Foligno.

Foligno made up for his error on his next shift, restoring Buffalo's lead with a nifty inside-out move to sidestep Deryk Engelland and then wristing a high shot past Chad Johnson on the glove side.

Calgary tied it once again on the first NHL goal for 18-year-old first round pick Matthew Tkachuk, who snapped a shot from off the wing that beat Lehner high on the short side.

"Obviously unbelievable," said Tkachuk about the feeling. "You dream about scoring in the NHL for a long time. Now that I've got he first one out of the way, hopefully we can just keep rolling as a team."

Michael Frolik also scored for Calgary (1-2-1), which continues its three-game homestand Thursday against Carolina.

Zemgus Girgensons and Ryan O'Reilly had the other goals for Buffalo (1-1-1). The Sabres play in Vancouver on Thursday.

The Flames outshot Buffalo 34-21. During one stretch while it was tied 1-1, the Sabres went nearly 18 minutes without a shot.

"I don't think there's many positives to take at all," said O'Reilly. "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."

Tied 1-1 after the first period, O'Reilly put the Sabres into the lead on a power play when his shot was stopped, but the rebound off Johnson's pad hit Hamilton in his chest and bounced into the net.

"They come out and get a fast goal in the third and they kept coming," said Lehner. "They had a little bit more jump than we did today. They looked a little faster."

Notes: Both teams squandered a 5-on-3 power play. Calgary finished 0-for-6 with the extra man. Buffalo went 1-for-5... Veteran defencemen Dennis Wideman and Nicklas Grossmann were scratches for the Flames as rookie Brett Kulak got in the line-up again. Wideman and Grossmann have a combined 1,350 games in their NHL career.