Lundqvist made 38 saves in regulation and overtime, and Zherdev, Dan Fritsche and Aaron Voros scored in regulation for New York.
Radek Dvorak, Jay Bouwmeester and David Booth countered for Florida.
The Rangers won their third consecutive game, while Florida lost for the fifth time in seven games.
Craig Anderson stopped 43 shots for Florida. He's 0-2 in shootouts this season.
Booth tied it at 3 with 1:33 left in the third. The Panthers had a 2-on-1 and Booth took a pass from Dvorak and got off a shot that went between Lundqvist's shoulder and the left post. Booth extended his goal streak to four games.
The Rangers took a 3-2 lead at 7:04 of the third when Voros picked up a loose puck at the left circle and put a wrister over Anderson's glove.
Florida had a 5-on-3 for 1:47 of the third, but the Rangers killed the penalty.
The Panthers tied it at 2 on Bouwmeester's power-play goal. His slap shot from the blue line deflected off a New York defenseman and bounced past Lundqvist and into the net with 1:03 left in the second, just 5 seconds into the power play. Bouwmeester has two goals in two games after failing to score in the 20 this season.
New York scored two goals in a 46-second span of the first.
Zherdev's backhanded shot from the right side crossed in front of the crease to the side of the net to make it 1-0 at 1:53. The second goal came on Fritsche's shot from just inside the left circle that beat Anderson on the stick side.
Florida closed to 2-1 when Ville Peltonen brought the puck out from behind the net. He passed to Dvorak in front and the puck deflected off Dvorak's skate and between Lundqvist's pads at 12:32 of the first. A video review upheld the goal.