NHL

Islanders find ‘third’ gear

What a difference a game makes.

After a shoddy third period cost the Islanders a win against the Flyers on Wednesday, they rebounded with one of their most complete final frames of the year yesterday, scoring twice in a 3-2 comeback win over the Penguins.

“I think that was the best period of hockey we’ve played,” goalie Dwayne Roloson said after John Tavares scored 13:48 into the third for the first game-winner of his young career.

Just as important as that third period was the penalty kill the Isles had in the second.

An interference penalty by Jack Hillen was followed barely a minute later by a double minor for high-sticking by Andy Sutton. With the Isles already trailing 2-1 against the defending Stanley Cup champs, they were dangerously close to their fourth loss in five games.

But the Isles, who face the Devils today in Newark, had the only real scoring chances in the ensuing minutes, and though they didn’t capitalize until the next period, the tone of the game had changed.

“After that, I said, ‘We have to learn from the other night, we have to continue this into the third,’ ” coach Scott Gordon said of the loss to the Flyers, in which they mustered just one shot in the final period.

Yesterday, they outshot first-place Pittsburgh, 37-21.

Sean Bergenheim scored on a wrister 1:24 into the third and then Tavares corralled a bouncing puck and put the Isles up for good.

“We turned it up a notch and played the way we need to play and got results,” center Nate Thompson said.

The Penguins entered yesterday’s game as winners of three straight and five of six.

“Any time you shut down players of their caliber, it’s great,” said Roloson. “But now, as a team, we’ve have to forget about it. That’s one game.”

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Sutton left in the third period with a groin injury that will be assessed today. Defenseman Andrew MacDonald was called up from AHL Bridgeport to take Sutton’s place.

dan.martin@nypost.com