PITTSBURGH — The much-maligned Pittsburgh Penguins’ penalty killers provided the lift needed to back up an already-sizzling power play.

The Penguins killed a lengthy 5-on-3 just minutes before Evgeni Malkin and Patric Hornqvist scored power-play goals 55 seconds apart in the second period, helping Pittsburgh hand the New York Islanders their first loss of the season, 3-1 on Saturday night.

“They took some heat the last three games, but certainly tonight they came through big time,” Penguins coach Mike Johnston said of the penalty killers. “That was the turning point in the game, that 5-on-3 kill.”

The Islanders (4-1), who came up empty during a 5-on-3 of their own in the second, were the Eastern Conference’s last unbeaten team.

“If you go back and look at our record when we don’t score a 5-on-3 goal, it’s not good,” Islanders coach Jack Capuano said. “We didn’t capitalize on ours, and obviously they did. That’s the difference in the game.”

Hornqvist, who assisted on Malkin’s goal, added an empty-net tally with 1:20 left to seal the Penguins’ win. It is the first time Hornqvist has opened a season with points in four straight games. He has a total of eight points.

Pittsburgh captain Sidney Crosby had two assists, including the 500th of his career. He joined Mario Lemieux and Jaromir Jagr as the only Penguins with 500 assists, and he is the sixth-fastest to do it in NHL history.

Marc-Andre Fleury made 30 saves as Pittsburgh recorded its fourth straight win over the Islanders and the eighth in nine meetings.

Thomas Hickey staked the Islanders to a 1-0 lead in the first period, but New York failed to post its first 5-0 start. Jaroslav Halak stopped 35 shots.

The Penguins’ penalty-killing unit, which ranked last in the league entering Saturday, went 6-for-6 in the game.