Joel Kwiatkowski, Bryan Allen and Jozef Stumpel scored for the Panthers in the 6-3 loss to Atlanta, the first home loss for the Cats this season.
Ilya Kovalchuk scored three power-play goals Monday night to help the Atlanta Thrashers continue the best start in franchise history.
Marian Hossa and Steve Rucchi also scored on the power play for the Thrashers, who also got a goal from former Florida captain Scott Mellanby. Vyacheslav Kozlov had four assists.
Atlanta finished 5-for-7 on the power play. The Thrashers entered the game 4-for-31 with the man advantage.
Florida, which entered the game first in the league in power-play efficiency at 27.9, was 0-for-6.
Atlanta is 3-0 against Florida this season. The Thrashers beat the Panthers 4-2 at Atlanta on Saturday night.
Kari Lehtonen, who has started every game for Atlanta, made 25 saves.
Florida goalie Alex Auld (3-3-1) gave up five goals on 19 shots before being pulled after the second period with the Panthers trailing 5-2. Ed Belfour stopped seven of eight shots in the third.
Atlanta trailed 2-0 before Kovalchuk scored his first goal at 17:55 of the first period on a one-timer from the slot.
The Thrashers then took advantage of a 5-on-3 to score twice in 36 seconds in the second.
Hossa tied the game at 2 with his sixth goal in four games when he took a pass across the crease from Mellanby. Kovalchuk then stopped a clearing attempt by Florida in the slot and beat Auld with a wrist shot just under the crossbar.
After Mellanby scored on a breakaway by taking a loose puck coming out of the penalty box, Kovalchuk completed his hat trick when he took a feed from Kozlov inside the blue line, skated in and beat Auld to the glove side.
Florida took a 2-0 lead with two goals in 23 seconds in the first period.
Kwiatkowski, a defenseman moved to forward because of injuries, opened the scoring when he tipped in Steve Montador's slap shot from the point.
Allen then scored on a 3-on-2 rush when he took Olli Jokinen's cross-ice pass and beat Lehtonen on the short side.
The Panthers now hit the road to visit the Northeast, facing the Rangers on Wednesday, the Devils on Thursday and the Islanders on Saturday.