Carter Hart made 27 saves for Philadephia. He had won his previous seven games.
"I liked our game," Flyers defenseman Matt Niskanen said. "I'd rather win, but we just went on a heck of a run, played pretty good hockey tonight. You can see how tight it's going to be when you play only good teams in about a month here. So it was a good test for us."
Rask made 12 saves in the third period.
"He's that caliber of goalie," Boston forward Charlie Coyle said. "The saves he makes ... I remember playing against him, and even in practice it's tough to score on that guy. He battles. He almost makes it look easy. That's a good team, been on fire, and the saves he had tonight were so huge."
Coyle made his own big save, racing back to break up a Flyers 2-on-0 shorthanded rush with 2:06 remaining in the second.
"I thought it was the play that may have changed the game," Bruins coach Bruce Cassidy said. "We don't know if they would have scored on that play, but it definitely gave us life on the bench, seeing an effort like that to keep the puck out of your net. I think it helped us at the other end."
Later in that Bruins power play, Grzelcyk gave the Bruins a 1-0 lead with 1:21 remaining in the second period.
"For two periods I felt we were the better team on the ice," Flyers coach Alain Vigneault said. "We had some good opportunities to take a lead, couldn't get anything past [Rask]. That goal that they got on their power play at the end of the second period seemed like it gave them confidence and momentum because in the third period they were the better team."
Bergeron made it 2-0 at 14:40 of the third period. Brad Marchand had an assist to give him 18 points (five goals, 13 assists) during a 13-game point streak, the longest active streak in the NHL.
