Boston had two third-period leads against Philadelphia disintegrate into losses already this season.
The Bruins wasted another lead against the Flyers on Monday night. Brett Connolly kept them from blowing the game.
Connolly redirected Zdeno Chara's shot from the point with 1:54 left, lifting Boston to a 3-2 win over Philadelphia.
Connolly tipped the wobbly shot and one-hopped the puck past Michel Neuvirth for his seventh goal of the season.
"I've been getting some good chances and to see that one go in such a big game is great right before the All-Star break," he said.
Boston has won five of six games as it tries to move up the Eastern Conference standings.
Brad Marchand scored a goal for the fifth straight game and Patrice Bergeron also scored for the Bruins.
Boston's Tuukka Rask stopped 34 shots in his return from a late scratch Saturday night with an undisclosed injury.
The Flyers had staged third-period rallies in a pair of wins over the Bruins in the first two meetings this season. Wayne Simmonds nearly made it a third time with two straight goals, including one in the third that made it 2-all.
The Flyers have lost three straight games after a solid 5-0-1 run put them in the hunt for a playoff spot. But they're closer now to the bottom of the standings than they are a playoff spot in a bunched-up conference.
Marchand has been fantastic since he returned from a three-game suspension for clipping Ottawa defenseman Mark Borowiecki. Marchand's five goals over five games bumped his season total to 20 and he also has an assist over the last six games.
Bergeron's 19th goal of the season came on the power play. Marchand added another power-play goal on a one-timer from the circle with 2:33 left in the first period.
Simmonds got the Flyers rolling early in the second when he scored his 13th goal at 3:45. His goal came on one of four power-play attempts for the Flyers in the first 11 minutes of the period.
"It was a tough 10 minutes for us," Rask said. "We battled through, we battled hard, and kept them at one goal so that's good."
Simmonds directed in a rebound with 7:52 left in the third. Simmonds has four goals in three games this season against Boston.
Boston coach Claude Julien went for the challenge because it appeared Flyers defenseman Michael Del Zotto had entered the offensive zone before the puck - and replay seemed to prove him correct.
The goal stood after a replay review for Boston's offside challenge.
The Flyers had turned a 4-2 deficit into a 5-4 overtime win and a 2-1 hole into a 3-2 victory earlier against the Bruins.
With Rask stout in the net, the Flyers could not muster one final comeback.
"We have to make sure we're getting ourselves up for the first periods and it starts with the first shift and it snowballs from there," Simmonds said.
With Steve Mason given the night off, Neuvirth stopped 28 shots. Neuvirth was limping after the game and did not appear in the locker room for interviews.
"Our goalies have been our MVPs so far this year," Simmonds said. "We know either one whoever goes in net you know they're going to give us a chance to win every single night."
NOTES: The Flyers celebrated "You Can Play Night." The You Can Play Project is an organization dedicated to changing the culture around LGBT athletes, coaches, and fans. The organization works to ensure equality, respect, and safety for all athletes, without regard of sexual orientation. Nellie Fitzpatrick, Director of the Mayor's Office of LGBT Affairs, was a special guest at the game. ... F Jordan Weal played for the Flyers for the first time since he joined the team in a Jan. 6 trade. ... The Flyers played their first game since Thursday. Their game Saturday in Brooklyn that was postponed because of a snowstorm has not yet been rescheduled. The Flyers play their ninth straight game against East teams Wednesday at Washington.