Oliver Wahlstrom had a goal and an assist for the Islanders (11-6-4), who salvaged a split of a two-game set and are the only NHL team without a regulation loss at home (7-0-2). Josh Bailey had two assists.
"It's been awesome," Wahlstrom said. "Every time I see my name in the lineup, it's really eye-opening. I really take that to heart. It's unbelievable to be in this locker room with these guys. I get confidence from everybody in this locker room, so it's been unbelievable so far."
Casey DeSmith made 28 saves for the Penguins (11-8-1), who lost for the first time in their past five games against the Islanders. Pittsburgh won 4-3 in overtime here Saturday.
"We played [them] last night, we know it's a great team to play against," Penguins center Evgeni Malkin said. "They play hard in the D zone, but for sure [that] was not our game. … It was a really slow start."
Wahlstrom gave New York a 1-0 lead on the power play when he one-timed Nick Leddy's pass at the left face-off circle at 19:20 of the first period. The goal extended Wahlstrom's point streak to four games (two goals, three assists). He leads NHL rookies with five power-play points (one goal, four assists).
"His confidence just continues to grow and he gets better and better," Bailey said of Wahlstrom. "He obviously has that big shot, and we all saw it tonight."
The Penguins did not have a shot on goal until Sorokin made a glove save on Pierre-Olivier Joseph from the left circle at 15:51 of the first period.
New York outshot Pittsburgh 9-2 in the first.
"If you talk to any goaltender or goaltending coach, they'll tell you one of the toughest games to play is when you haven't been busy," Islanders coach Barry Trotz said. "It's easy to sort of let your mind wander and all that, and I think Ilya did a really good job."