The Islanders’ stirring run of comebacks from two-goal deficits incredibly continued Sunday night against the two-time defending Stanley Cup champions.

And this one mostly was about their budding superstar defenseman.

Just as they’d done in Montreal and Columbus earlier this week — albeit this time without the need for overtime — rookie phenom Matthew Schaefer and the surging Isles stormed back from a 2-0 hole again before posting their fifth straight victory bridging the Olympic break with a rousing 5-4 decision over the Panthers at UBS Arena.

Florida’s Sam Reinhart evened the score with just under two minutes to play, but Isles captain Anders Lee’s forehand move with 30.9 seconds left in regulation improved the Isles to 35-21-5 overall ahead of a West Coast trip beginning Wednesday in Anaheim, Calif.

“These are some big games,” said the 18-year-old Schaefer, who scored twice to become the first Isles defenseman of any age to reach 20 goals since Denis Potvin in 1985-86. “A couple of big days, obviously, a couple of overtimes. … The last couple of games we’ve been down by a couple of goals and just fought back. It’s a team effort.”

New York Islanders player Anders Lee (#27) scoring the game-winning goal against Florida Panthers goalie Sergei Bobrovsky (#72).Anders Lee scores the game-winning goal during the Islanders’ March 1 win. NHLI via Getty Images

Schaefer’s second goal of the night and 20th already of his first professional campaign with just over nine minutes remaining in regulation snapped a 3-3 tie.

After the Isles forced a turnover in the Florida zone, Ondrej Palat found Schaefer, who whistled a wrister off a Panthers player and between the legs of veteran goalie Sergei Bobrovsky to spark loud chants of the rookie’s name multiple times.

“I have to stay dialed in, but when I hear that from the crowd, it gets me super fired up,” Schaefer said. “It’s so fun. I want to hear that every night.”

Sandis Vilmanis and Sam Bennett had staked the Panthers to a 2-0 advantage against Isles backup goalie David Rittich before the 15-minute mark of the opening session.

New York Islanders defenseman Matthew Schaefer celebrates his goal with teammate Ryan Pulock (6).Matthew Schaefer celebrates his goal during the Islanders’ March 1 win. Heather Khalifa for the NY Post

Schaefer, who also broke Phil Housley’s league mark Thursday in Montreal for goals by an 18-year-old blueliner, fired in a pinball goal with a slapper from the right circle that hit a Florida defenseman, then the crossbar and then the back of Bobrovsky before settling across the goal line for a 2-1 game with less than two minutes left before intermission.

”I don’t know how many times I’ve said the word ‘impressive,’ ” Isles coach Patrick Roy said of Schaefer. “But he’s doing things that are very special out there.”

Before the game, two-time Cup-winning coach Paul Maurice added himself to the growing list of admirers of the dynamic rookie, who now stands just three goals behind Rangers legend Brian Leetch’s 23 for the all-time NHL mark for rookie defenders.

“It’s just awesome,” the Panthers’ bench boss said. “When they’re 18, and they can do that — like pure 18 and step in the league and be an impact player at that age — he’s just going to get better and better and better. But he’s not afraid to shoot the puck, not afraid to get up the ice.

“He’s smart, like, not all offense regardless of the situation. He’s got a really good balance, like, he’s played in the league for a whole bunch of years. He knows when to go and when not to go. So the Islanders got a cornerstone for their franchise for probably 20 years.”

On the ice from Long Island

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Carson Soucy buried the equalizer with a 4-on-4 goal barely seven minutes into the middle period after Schaefer’s interference penalty had negated an Isles power play.

It was Soucy’s second in nine games with the Isles since a late-January trade from the Rangers and his fifth overall this season.

Bennett buried his second of the game with a backhander off the rush around the 12-minute mark of the second, but Bo Horvat made it a 3-3 game with a hard-angle shot from the left wall past Bobrovsky with just under three minutes to play before intermission.

“I hope it’s not something we do every night,” Roy said of the comeback run. “But I love the fact we don’t change our game and stay focused and do what we have to do.”