New York, on the verge of elimination in the Eastern Conference playoff race, bounced back quickly from Quinton Howden's short-handed goal less than two minutes in and sent the Panthers to their fourth straight loss.
Travis Hamonic, Matt Martin and Mike Halmo also scored, Colin McDonald had two assists, and Evgeni Nabokov made 20 saves for the Islanders, 4-0-1 in their past five games. Florida, which won the two earlier meetings this season, is one of only three NHL teams with fewer points than New York.
Brandon Pirri closed the scoring for Florida, making it 4-2 with his 11th goal - on a power play - with 5.9 seconds left in the game. Scott Clemmensen stopped 36 shots for Florida, which lost 6-3 at New Jersey on Monday.
The Islanders shook off the early deficit and got even 45 seconds later on the same power play when Hamonic netted his third goal.
The action started quickly for the Panthers, who scored short-handed for the second straight night - the fourth time that has happened in team history.
Howden knocked the puck free at the left point and raced the other way alone. He easily stayed in front of Frans Nielsen and beat Nabokov at 1:50.
That lead was short-lived as Hamonic connected late in the power play. Bailey won a faceoff in the right circle and got the puck back to the right point to Hamonic, who glided into the middle and snapped a shot through traffic at 2:35.
Florida gave the Islanders two other power plays in the period in which the Panthers were outshot 11-5.
They were about to get an advantage with 2:19 left in the first when Matt Carkner high-sticked Scottie Upshall in front of the penalty box and knocked him to the ice. But Panthers teammate Erik Gudbranson charged Carkner, and they immediately dropped the gloves and fought.
Gudbranson was given an extra penalty for instigating, wiping out the impending power play.
The Islanders added two goals in the second, including Bailey's seventh that came 17 seconds after he left the penalty box. McDonald got two whacks at the puck in close, and Bailey found the rebound and slammed in the goal at 11:18.
New York stretched the lead to 3-1 with 2:24 remaining. McDonald knocked the puck away from Racine at the left point and took off alone. The hard-charging Martin came down the middle and ripped in the rebound of McDonald's shot for his eighth goal.
Halmo converted his rebound 4:21 into the third to make it 4-1. It was his first NHL goal in his 13th career game.
NOTES: For the third straight season, Martin was presented with the team's Bob Nystrom Award, given to the Islanders player who best exemplifies leadership, hustle and dedication. ... Nabokov was the third Islanders goalie in three games to start against the Panthers this season. ... Racine and RW Bobby Butler were both recalled from San Antonio (AHL) on Tuesday. Butler was scratched.