Philadelphia's Claude Giroux and New Jersey's Jason Arnott each scored in the third round of the tiebreaker to force an added round.
Adam Mair, Dainius Zubrus and Jamie Lagenbrunner scored in regulation for the Devils, erasing New Jersey's two-goal deficit and putting the defending Eastern Conference champion Flyers behind entering the third period.
Danny Briere tied it 3-3 at 13:54 when he beat Johan Hedberg to the glove side for an unassisted goal. Darroll Powe and Jeff Carter scored in the first period for the No. 7 Flyers, who eliminated the second-seeded Devils in the first round of last season's playoffs.
"We were slow in the first half," Flyers coach Peter Laviolette said. "We reacted slowly. I thought the third period changed that, and the overtime."
Michael Leighton stopped 20 of 23 shots for the Flyers, and Sergei Bobrovsky -- who is competing to be Leighton's backup -- turned aside all seven shots he faced in the third period and overtime.
Johan Hedberg made 11 saves on 13 shots for New Jersey, but Mike McKenna allowed the tying goal in the third period.
"The first two periods were tough to get the competitive edge, get our nose into the battle," Briere said. "Once we did, I thought we took control of the game."
The intensity seemed high for a preseason game, with several players involved in fights. New Jersey's Pierre-Luc Letourneau-Leblond and Philadelphia's Matt Walker mixed it up in the first, and Letourneau-Leblond and Jody Shelly fought in the third.
"It's fun for guys to come in and show what they can do, to come in and play some Flyers hockey," Briere said. "And the fact that we're playing New Jersey, just down the highway from us ... there's a big rivalry with what happened last year in the playoffs.
"It was good to put a little bit of entertainment out there on the ice."
Copyright by STATS LLC and The Associated Press
Arena: Wells Fargo Center Location: Philadelphia, Pennsylvania
Referees: David Banfield, Paul Devorski Linesmen: Tim Nowak, Tony Sericolo
Attendance: 19,288 (98.9% full)
Darroll Powe 1 Assist: Claude Giroux
Jeff Carter 1 Assist: Kimmo Timonen, Braydon Coburn
Adam Mair 1 Assist: Henrik Tallinder, Alexander Urbom
Dainius Zubrus 1 Assist: David Clarkson, Matthew Corrente
Jamie Langenbrunner 1 Assist: Henrik Tallinder, Alexander Urbom
Daniel Briere 1 Unassisted
No scoring this period
Daniel Briere shootout attempt against Mike McKenna: SAVED.
Jamie Langenbrunner shootout attempt against Sergei Bobrovsky: SAVED.
Nikolai Zherdev shootout attempt against Mike McKenna: SAVED.
Patrik Elias shootout attempt against Sergei Bobrovsky: SAVED.
Claude Giroux shootout attempt against Mike McKenna: GOAL.
Jason Arnott shootout attempt against Sergei Bobrovsky: GOAL.
Mike Richards shootout attempt against Mike McKenna: GOAL.
Jacob Josefson shootout attempt against Sergei Bobrovsky: SAVED.