Milan Lucic scored the winning goal at 17:03 in the third period. Lucic, taking advantage of the Flyers' third line of defense, scored on a turnaround slap shot that blew by Flyers goalie Brian Boucher to break a 2-2 tie.
Boston scored the opening goal at 05:12 in the first period. Patrice Bergeron won the faceoff from the left circle in the Philadelphia zone. Bergeron then fed a quick pass back to teammate Johnny Boychuck, who put a quick slap shot past Boucher.
Flyers captain Mike Richards tied the score at 1-1 at 17:06. With teammate Danny Brier setting a screen on Bruins defenseman Vladimir Sobotka, Richards found an open area and rifled a snap shot into an opening on Bruins goalie Tuukka Rask's stick side.
Bruins right wing Miroslav Satan scored his fourth goal of the playoffs to give Boston a 2-1 lead in the second period.
The Bruins did a nice job with puck possession in their opponents' zone. Matt Hunwick kept the puck alive and fed a cross ice pass to teammate Dennis Wideman, who then fed a pass up to Blake Wheeler. Wheeler slung a crisp pass to an open Satan, who buried it in the net.
Philadelphia tied the score at 2-2 with less than a minute remaining in the second period. Ville Leino was rushing up center ice and found Brier crashing the net to his right. Satan, chasing Brier, couldn't quite knock the puck away from the Flyers right wing. Brier scored on a snap shot at 19:35.
Boston continued to play well on the penalty kill. The Bruins, who allowed two power play goals in Game One, allowed none in Game Two, killing four penalties.
Game Three is set for Wednesday night in Philadelphia.