Joffrey Lupul scored the go-ahead goal in the third period, Antero Niittymaki made 29 saves to remain perfect against Atlanta and the Flyers snapped the Thrashers' five-game winning streak with a 4-3 victory Sunday night.
Simon Gagne had a goal and two assists, Mike Knuble had a goal and an assist, and Kimmo Timonen also scored to help the Flyers to their second straight victory and third in four games.
Erik Christensen, Bryan Little and Vyacheslav Kozlov scored for Atlanta, which had dropped six straight games before its five-game streak.
Kozlov hammered in a rebound at 12:03 of the third period to pull the Thrashers back from a two-goal deficit to a 3-3 tie.
One minute later, Lupul skated in from centre ice, slipped around a defender at the faceoff circle and put a slap shot from the slot between goalie Johan Hedberg's pads.
Niittymaki, who blanked the Thrashers 7-0 with 24 saves earlier this season, is 11-0 against Atlanta. He stopped 21 shots in the third period.
Niittymaki is one of only two active goaltenders in the NHL with a perfect record in at least 10 decisions against one team. Chris Osgood, of the Detroit Red Wings, is 17-0 against Tampa Bay.
Niittymaki helped preserve the Flyers' lead in the second period when the Thrashers had a two-man advantage for 1:12. He's 2-1-2 this season.
Hedberg had 28 saves for Atlanta.
Gagne scored unassisted to put the Flyers ahead 53 seconds into the first period. He picked up a loose puck deep in the Flyers' zone, skated in and went forehand to backhand for his 11th goal.
Knuble made it 2-0 with 7 seconds left in the period. He scored his seventh goal on a wrist shot from the left circle after taking a cross-ice pass from Gagne.
Christensen got Atlanta on the board at 5:45 of the second period when his shovel shot from the slot trickled past Niittymaki. It was his first goal in 19 games dating to last March.
Timonen put the Flyers ahead 3-1 with a slap shot from behind the left circle on a power play at 11:27. Knuble picked up his 200th career assist on the goal.
Little got Atlanta to within 3-2 with a fluke goal 35 seconds into the third period. Niittymaki stopped his first shot, but the puck bounced off Philadelphia defenceman Luca Sbisa back into the net.