Mike Richards, the first Flyers shooter, was stopped by Martin Brodeur and that proved decisive. Jeff Carter and Danny Briere followed with goals, but it wasn't enough to extend Philadelphia's winning streak.
Johnny Oduya had his first two-goal game for the Devils and Jamie Langenbrunner also scored in regulation.
Mike Knuble sent the game into overtime, scoring the equalizer for Philadelphia with 55.2 seconds remaining and Biron on the bench for an extra attacker. The Flyers relentlessly pounded the Devils defense and the pressure paid off as Richards fed the puck from behind the net to Knuble in the slot. He whipped a shot past Brodeur to make it 4-4.
Vinnie Prospal, Jim Dowd and Randy Jones also scored for Philadelphia in regulation time.
Gionta gave the Devils a 4-3 lead with 5:53 left in regulation. Brodeur started the play with an outlet pass, and Gionta left a drop pass for John Madden in the Flyers zone. Gionta then headed to the net and deflected in the return feed.
The Devils jumped over Ottawa into fourth place in the Eastern Conference playoff race. Philadelphia is in seventh, two points behind the New York Rangers and one ahead of Boston.
Oduya scored twice in the first period as the Devils rallied for a 2-1 lead.
Philadelphia opened the scoring at 9:35 on Prospal's goal.
Oduya pulled the Devils even on a power-play goal with 2:39 remaining. He threaded a pass through the crease intended for Zach Parise, and the puck popped past Biron.
Parise set up Oduya's second tally, sending a pass back to the point where the defenseman cranked a shot past Biron with 31.2 seconds remaining.
In the second, Langenbrunner made it 3-1 at 3:25, knocking in a rebound of Sheldon Brookbank's shot.
Dowd, a New Jersey native and a former Devils player, got the Flyers back in the game with a deflection of Jones' shot at 9:14.
Jones evened it 3-3 at 8:18 with a shot from the left point over Brodeur's glove. It looked as though Carter might have deflected the puck with a high stick but a video review upheld the goal.
