The Islanders faltered early and never caught up.

A two-goal first period from the Penguins was all it took to rattle the Isles, who were uncharacteristically careless with the puck to start the game and ultimately fell 2-1 Tuesday night in Pittsburgh.

By the time the Islanders settled down and began generating scoring chances, the Penguins had already adopted a bend-don’t-break mentality that helped them fend off anything that was thrown their way.

Even when the Islanders were gifted their first power play of the game with less than two minutes left in regulation, after Penguins forward Bryan Rust was called for closing his hand on the puck, the team couldn’t capitalize on the six-on-four opportunity with their net empty.

The equalizer never came, so the series is tied 1-1 heading to Long Island.

“At the end of the day, I just thought they had more desperation in their game,” head coach Barry Trotz said after the loss. “We were a little bit light in some areas and we didn’t make it hard enough on them. We’ve got to raise our level, we have that. I was just disappointed that we didn’t get our level to the level that we needed it.”

Trotz wasn’t thrilled with the Isles’ start in Game 1, either. Series-opening jitters could be an explanation for Sunday, and then PPG Paints Arena increased its capacity to 50 percent Tuesday. But the slow starts will have to be rectified.

“There’s no magic pill that I can give everybody to take and we’ll have a good start, it comes from within,” Trotz said. “They’ve got to simplify, they’ve got to be ready to go.”

Pittsburgh, as it had in Game 1, led 2-1 at the start of the third. This time around, they kept the Islanders out of their zone and maintained pressure for a majority of the final frame.

The Islanders managed to tighten up their game in the second period, with Josh Bailey making it a one-goal contest after cutting to the slot and backhanding the puck in over Jarry’s left shoulder at 14:44, but the team wasn’t able to build on it.

In his series debut, Semyon Varlamov put on a clinic in the third period, which allowed the Islanders to stay competitive after falling into a 2-0 hole. Varlamov, who was scratched in Game 1 out of precaution due to the lower-body injury he sustained in the regular-season finale, made 16 of his 43 saves in the third period.

The Penguins had the Islanders out of sync through the first 20 minutes, beating them on the walls and forcing turnovers in their defensive zone. Defenseman Ryan Pulock coughed up the puck to Rust for a shot that soared over Varlamov’s glove to make it a 1-0 game at 3:22. Jeff Carter then doubled the Penguins’ score after a strong forecheck, skating in front of the crease and going five-hole on Varlamov.

Trotz noted that the Islanders will have to stop easing into the game and establish themselves right away.

“Getting a split was crucial,” Trotz said. “I don’t think anybody would come in here [and say], ‘Hey, we’re going to win both.’ You go in with the plan to win both, but it doesn’t happen a lot.

“You look around the NHL right now, in almost every series, there’s been some splits. That’s the NHL, it’s going to be a dogfight, it’s going to be the team that stays with it.”