ille Leino scored the go-ahead goal 2:17 into the third period by having a rebound go in off his skate after Ryan Miller stopped Briere's initial shot from the left circle on a 2-on-1 break. Scott Hartnell scored twice, including an empty-netter, and Mike Richards also scored as the Eastern Conference-leading Flyers (27-10-5) won their fourth straight and 12th of their past 16 (12-3-1).
Sergei Bobrovsky stopped 38 shots in making his first start in four games since allowing five goals on 27 shots in a 5-2 loss at Anaheim on Dec. 31.
Cody McCormick had a goal and an assist, and Paul Gaustad also scored for Buffalo (18-19-5), which led 2-0 before the first period was 10 minutes old. The Sabres lost in regulation for the first time in six games (4-1-1), and lost for the second time this season when leading by two.
Leino's go-ahead goal came as he was driving to the net a step ahead of McCormick. Though Leino moved his right skate in an attempt to kick the puck in, the puck glanced in off his left skate. The goal was reviewed and allowed to stand.
Briere tied the game late in the second period by roofing a shot over Miller's left shoulder to convert Kimmo Timonen's pass on a 2-on-1. Briere, who still gets a few boos from the crowd in Buffalo, is the Sabres' former co-captain who left in free agency in the summer of 2007 to sign with the Flyers.
The Flyers rallied after getting off to a flat start in which they were outshot 12-3 and outscored 2-0 at the 9:59 mark of the first period when McCormick, to the left of the net, banked the puck in off the back of Bobrovsky's pad.
Hartnell's goal finally got the Flyers on the board, deflecting in Timonen's point shot on a power play 12:41 into the first period. Richards set up the play by bowling over Buffalo's Jochen Hecht in the right corner to create a turnover.
Richards sealed the win scoring on a breakaway with 8:24 remaining.
NOTES: The Flyers kicked off a four-game road trip and are in the midst of playing nine of 10 away from Philadelphia. ... The Sabres didn't have a player selected to play in the All-Star game at Raleigh, N.C. on Jan. 30, but did have rookie forward Tyler Ennis selected to compete in the skills competition a day earlier. ... Flyers RW Nikolay Zherdev is traveling with the team but missed his fourth straight game with a groin injury. ... Through the 15-minute mark of the second period, McCormick was credited with eight of Buffalo's 24 shots.