The Thrashers have won four straight since a six-game losing streak dropped them to ninth in the eight-team race for playoff spots. The Bruins beat the New York Rangers 2-1 earlier Sunday.
Mike Richards scored for Philadelphia. Though the Flyers and Ottawa are tied with 79 points, the Flyers fell to sixth seed with 11 games remaining.
Hainsey opened the scoring 2:04 into the game on a wrist shot from just inside the faceoff circle that beat Brian Boucher to the stick side.
A little more than 9 minutes later, White took a pass at center ice from Jim Slater, skated down the right side, and fired it through Boucher's legs.
Richards pulled the Flyers within a goal with 8:04 left in the game. He took a behind-the-net feed from Matt Carle and flipped it over Pavelec's outstretched glove.
Peverley scored with 3:07 left, using Carle as a screen to flick a wrist shot past Boucher, and sending many Flyers fans to the Wachovia Center exits.
Philadelphia also lost 5-2 in Atlanta on Sunday. They have lost all four times to the Thrashers this season, after a 14-game winning streak.
Philadelphia tied a season high with 45 shots. Boucher made 28 saves. He fell to 1-2-1 since replacing the injured Michael Leighton last week.
NOTES: The Flyers are 14-3-2-1 at home against Atlanta. ... Thrashers center Nik Antropov had his multipoint streak snapped at four games. ... Carle has scored a point in six of his past nine games.