The loss leaves the Isles (23-24-8) eight points behind the Toronto Maple Leafs for the No. 8 seed in the East. New York -- which went 1-2-0 on the homestand -- plays its next two games on the road, starting with Tuesday's match at Winnipeg.
"These games are so important this time of the year and where we are in the standings," said Isles center John Tavares, who has now gone six straight games without a goal. “There's no excuse for us not to be ready to play or have our feet moving or having our game going off the bat. We have to improve in that area."
Florida's Jose Theodore made 26 saves in his first appearance since Jan. 20 after suffering a knee injury.
The Panthers' quick-strike offense supported Theodore with two goals off faceoffs and four unanswered goals overall to erase a 1-0 deficit.
The Panthers swept a set of back-to-back games for the first time in nine attempts this season after defeating the New Jersey Devils on the road Saturday. Florida also remained in sole possession of first place in the Southeast Division – and third place in the conference – with 65 points. The Panthers extended their division to four points lead thanks to the New York Rangers' 3-2 win against Washington.
"It was a good weekend for us … that was two solid games," Florida coach Kevin Dineen said. "It's satisfying. You go out, you play hard and you get rewarded like that. I thought our all-around effort was good."
Frans Nielsen scored the Islanders' goal on the team's first shot at 3:35 of the first, when he converted PA Parenteau's pass for his 10th goal of the season.
But Strachan notched his first career goal later in the first and Fleischmann, Versteeg and Skille scored three goals in a 14:16 span in the second period to turn a tie game into a 4-1 advantage heading into the final period.
Making his fourth start in six days, Islanders goalie Evgeni Nabokov allowed three goals on six shots in the second and made just 11 saves on 15 shots total before being lifted for backup Al Montoya to start the third.
The 36-year-old Nabokov entered the game having allowed only five goals on 135 shots in five games since the All-Star break. He allowed his fourth goal of the game with 1:27 left in the second on Skille's strike off a draw.
"They probably had seven or eight scoring chances, and they scored four goals," Nabokov said. "That was the difference right there."
Fleischmann tipped in Versteeg's pass from the left post for his 18th goal to break a 1-all tie 4:17 into the second.
Versteeg tied a career high with his 22nd goal on a right-circle wrister on a power-play goal at 11:41.
Tomas Kopecky screened Nabokov as Versteeg's shot beat him on the high glove-side.
Fleischmann and Versteeg each finished with two points.
"Two good games -- 60 minutes -- by every line," Fleischmann said.
Strachan's right-point slap shot off Marcel Goc's faceoff win erased a 1-0 deficit at 14:57 of the opening period. Goc has three assists in his past two games.
"You give up two faceoff goals and a power-play goal, you're not going to win too many games," Isles coach Jack Capuano said. “We had our chances, we didn't bury."
Material from wire services and team media was used in this report.
1 - 0 NYI
1 - 1 Tie
2 - 1 FLA
3 - 1 FLA
4 - 1 FLA