The Flyers, roared on by an orange-clad home crowd of more than 20,000 after dropping the first two games of the series in Chicago, won a see-saw battle when Claude Giroux scored 5:59 into the sudden-death period.

Giroux's shot off a crisp pass from Matt Carle beat goalie Antti Niemi just 57 seconds after officials used replay to confirm that Flyer Simon Gagne's shot that ricocheted off a Chicago defender and banged off the post had not crossed the goal line.

The Flyers, seeking their first NHL title since 1975, came right back after the video review to mount their game-ending rush down the ice.

"This was a big game for us, we really needed that win," said 22-year-old Giroux. "It was tough losing the first two games and we knew we had to win tonight.

"It's probably the biggest goal of my career."

Game Four of a pulsating series, in which each game has been decided by a one-goal margin, will be played on Friday in Philadelphia.

"They (Chicago) probably thought they could have won tonight but I thought we could have won both games up there," Flyers coach Peter Laviolette told reporters.

"I'm 100 percent confident of the guys in this team to win any game."

Chicago coach Joel Quenneville said the hard-hitting game was a toss-up.

"The game was on the line from start to finish, as all three games have been," he said. "Tonight was one of those games that could have gone either way."

It was Philadelphia's sixth win in a row at home and denied the Blackhawks an NHL record eighth successive road victory in the playoffs, which would have moved them within one win of their first Cup triumph in 49 years.

Chicago, seeking to end the NHL's longest title drought, overcame 1-0 and 2-1 deficits before levelling the game heading into the final period, where the teams traded goals within 20 seconds of each other early in the stanza to make it 3-3.

Daniel Briere, Scott Hartnell and Ville Leino scored in regulation for Philadelphia, while Duncan Keith, Brent Sopel and Patrick Kane found the net for Chicago in a hard-hitting contest.

The Flyers, who scored on their only shot on goal of the overtime, outshot the Black Hawks 31 to 25 in the game.