PHILADELPHIA -- The Buffalo Sabres are already making strides just nine games into the season.

One of those strides came Tuesday night when they showed plenty of resolve by taking down the Philadelphia Flyers in a thrilling 4-3 overtime victory at Wells Fargo Center.

And for the first time in three seasons, Buffalo has won three or more games in October.

"We're learning how to win as a group," Sabres coach Dan Bylsma said. "We're developing a team and how we want to play."

Center Zemgus Girgensons potted the game-winner in the 3-on-3 extra session on a breakaway.

"The whole team gave it their all," Girgensons said. "It would've been better if we didn't go to that overtime, but it's good to get that win."

Center Tyler Ennis, left winger Jamie McGinn and defenseman Jake McCabe also scored goals to lead the Sabres (3-6-0) to their first road win of the season. The previous two seasons, Buffalo won just a pair of games in the first month of each.

The Flyers (4-2-2), who entered 10-2-1 in their last 13 games against the Sabres, had their two-game winning streak snapped. This coming after they beat the New York Rangers and Boston Bruins.

"We have to find a way to be prepared for it as if we were playing the Rangers or Chicago (Blackhawks) or Pittsburgh (Penguins)," right winger Jakub Voracek said. "It's an NHL hockey team."

Is it difficult to get up for some opponents compared to the rivals?

"That shouldn't make a difference to anybody," Flyers coach Dave Hakstol said. "We know they're a good hockey team, so, not to me it doesn't make a difference."

After Philadelphia erased Buffalo's two-goal lead, the Sabres quickly answered midway through the third period when McCabe fired a snap shot past goalie Steve Mason to make it 3-2. But the Flyers countered with a goal by center Brayden Schenn, his second of the third period, with 54 seconds remaining to send the game to overtime.

However, the Sabres' confidence never wavered.

"It's sticking with it, not getting down on each other after a goal and coming back the next shift and putting the pressure on," McGinn said. "We have a lot of skill in this room and a lot of heart."

Sabres goalie Chad Johnson (3-5-0) made 30 saves for the win. He was coming off a nightmare performance in which he allowed seven goals to the Montreal Canadiens.

Mason (2-2-2) took the overtime defeat after winning two straight games. He made 36 saves.

In the 3-on-3 overtime, Girgensons got a golden look and put it past Mason.

"I don't think any goalie (likes it) to be honest," Voracek said of the 3-on-3 format. "It's a lot of scoring chances."

Sabres center Tyler Ennis scored a funky goal to get things started in the first period. As the 26-year-old received a pass behind Philadelphia's net, he wildly spun and lost his balance but found a way to wrap around and sneak the puck past Mason for a 1-0 lead.

Buffalo tacked on not long after by making the Flyers pay for a two-minute roughing penalty charged to center Claude Giroux. The Sabres put precision passing on display when McGinn tipped in a man-advantage goal off a touch pass from left winger Johan Larsson to make it 2-0.

That early lead didn't last, but it didn't stop Buffalo from leaving with a victory.

"It just shows the character we have," Girgensons said. "And the ability to win."

NOTES: Flyers RW Pierre-Edouard Bellemare left the game in the first period with an upper-body injury and did not return. ... The Flyers honored former C Danny Briere, who retired in the offseason. The 38-year-old played in 17 NHL seasons, including six with Philadelphia and four with the Buffalo Sabres. Briere is second in Flyers history with nine game-winning goals in the Stanley Cup playoffs. ... The Sabres played their first game without star LW Evander Kane, who is out four to six weeks with a knee injury. LW Nicolas Deslauriers filled Kane's spot on Buffalo's top line. ... Flyers LW Michael Raffl was in the lineup after leaving the previous game on Oct. 24 with an upper-body injury. Raffl was incidentally elbowed in the head and collapsed on the bench. ... Sabres rookies C Jack Eichel and C Sam Reinhart were paired on Buffalo's second line. Eichel was selected No. 2 overall in the 2015 NHL draft and Reinhart was the No. 2 overall pick in 2014. ... Flyers C Sean Couturier missed his second straight game after suffering a concussion on Oct. 21. He's considered day to day.