He went for his signature move — a one-handed backhand shot away from his body — to slip the decisive goal past Jaroslav Halak in the fifth round and give the Panthers a 3-2 win on Friday night.
"It has worked a couple of times before and I thought it should work this time, too," said Barkov, who scored a power-play goal in Florida's 3-1 loss to Los Angeles last Monday. "There was no pressure at all. I just knew what I was going to do and it worked."
Roberto Luongo stopped Brock Nelson's shot to end the game for his 408th win, moving him past Glenn Hall on the NHL victories list.
Brandon Pirri, Vincent Trocheck, Nick Bjugstad and Jonathan Huberdeau also scored in the shootout for the Panthers, who won for the third straight time against the Islanders.
Barkov was surprised to see nine goals in the shootout.
"That's the first time I've seen that," he said. "I think the fans were happy."
Islanders' scorers in the shootout were Frans Nielsen, Kyle Okposo, John Tavares and Josh Bailey.
"I know it was very entertaining for the fans," said Florida coach Gerard Gallant. "We needed those two points and we got them. It's been a tough stretch."
With Florida ahead 2-0 after two periods, the Islanders stormed back with a pair of goals just over three minutes apart in the third.
Ryan Strome beat Luongo high to the glove side for his second goal of the season to cut the deficit to 2-1 with 5:36 gone, and Josh Bailey converted on a one-timer in traffic for his fourth to tie it up at 8:39.
Brandon Pirri, who has points in all four of his games against the Islanders, gave Florida a 1-0 lead 8:38 into the first period. It was his fourth goal this season and third against New York in his career.
Pirri beat Jaroslav Halak on a wrist shot from the top of the right circle. Jaromir Jagr picked up his 10th assist, with Erik Gudbranson adding his third.
"We won, so we're good," said Pirri, who was moved to the first line by Gallant. "It was real easy to play with those guys. They communicate so well and their hockey IQ is so good, it'd be hard to screw that up."
The Panthers went up 2-0 at 4:42 of the second period when Jussi Jokinen tipped in a perfect feed from Vincent Trocheck behind the net for his 10th goal.
Islanders coach Jack Capuano was as surprised by the nine-goal shootout as anyone.
"It just seemed like goals kept coming," Capuano said. "Fortunately for them they got the one they needed."
Notes: Jagr's assist on Pirri's goal was the 1,090th of his career. He has eight points in his last eight games and 154 total in 108 contests against the Islanders. ... Luongo played his 882nd NHL game, tying him with former Panthers' netminder John Vanbiesbrouck for eighth place all-time.