PITTSBURGH — Jaroslav Halak has been back with the Islanders for 48 hours, and he’s already made a difference.

Halak made 37 saves, plus two more huge ones in the shootout, to lead the Islanders to a 4-3 win over the Penguins on Friday night. It lifted the Isles back into the final wild-card playoff slot in the Eastern Conference. The Islanders and Boston have 82 points each, but the Isles have played one fewer game. The two teams will face off Saturday night in Brooklyn.

“Obviously I’m happy. It’s great to be back,” Halak said after a dizzying overtime in which he made six stops, every one off a dangerous scoring chance for the Penguins. “It’s a big win, a big two points, and I thought we played a good game.”

Although the Penguins tied the score on Matt Cullen’s rebound goal with 6:10 left in the third period, it was one of the Isles’ better performances in recent weeks. They pumped 46 shots on Marc-Andre Fleury, 21 in the third period as they spent the first 13 minutes and change hunting for a two-goal lead that never came.

But even after the wild OT, with Halak closing his pads to somehow deny Cullen the possible winner with 1:49 left, the Isles needed some shootout magic. Anthony Beauvillier and John Tavares beat Fleury, Sidney Crosby scored, and Halak — making his first NHL appearance since Dec. 29 — had to stop Nick Bonino in round three to win it. He did, just barely.

“He got us the two points we really needed,” said Casey Cizikas, who gave the Isles a 3-2 lead with 4.5 seconds left in the second period off a nice feed from Tavares. “He was huge.”

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The game had some wild moments, mostly involving coach’s challenges. Brock Nelson appeared to give the Islanders a 1-0 lead with 1.7 seconds to go in the first period, but Penguins coach Mike Sullivan challenged for goaltender interference. After a review, the goal was waved off, with the refs contending that Alan Quine interfered with Fleury.

Doug Weight disagreed with the call. Vehemently.

“I still think it’s a goal,” Weight said. “But you gotta move on.”

The Islanders did, rallying after Cameron Gaunce beat Halak from long range 1:54 into the second period. Nelson whipped one by Fleury at 4:48 and Anders Lee gave the Isles the lead at 9:18, though Sullivan again challenged, this time for offside.

It certainly looked as if he would win that one as well, with Lee clearly lifting his skate off the blue line well before the puck entered the zone. But Lee got his skate back down onside before Josh Bailey touched it, so the goal stood, to Sullivan’s surprise.

Crosby tied it at 13:41 and Cizikas untied it in the closing seconds before Cullen evened the score late in the third.

There definitely was some relief when Halak closed the pads on Bonino, for both the goaltender back from exile in Bridgeport and the team back from the depths in the playoff race. It was the Islanders’ 20th win in 31 games under Weight.

“I’m looking up and it’s 3-3 and I’m thinking, ‘Don’t let it slide in off someone’s foot,’ ” Weight said. “We deserved this one. Not a slight to them, but we got what we deserved tonight.”