In six games since returning from an upper-body injury, McCann has played second-line center in place of Evgeni Malkin (lower body). The Penguins are 5-1-1 without Malkin.
"We're playing a complete game," McCann said. "We're doing the simple things to win the game. I know it sounds pretty cliche, but we're working as a team. ... We're doing all the right things to help each other and we're taking advantage of their mistakes and capitalizing."
New York has trailed 2-0 after the first period in each of its past three games.
"Obviously, we're not trying to do it," Islanders defenseman Ryan Pulock said. "But it's something that we have to stop now and really focus on the first five minutes, first 10 minutes next game, and coming with our best to start."
Martin cut it to 2-1 by tipping in a pass from Mathew Barzal on a power play at 9:22 of the second period. Martin hadn't scored a point in his previous eight games.
"I just think we're not getting off to the best starts," Martin said. "We have a lot of character in our room. We eventually find our game and get to our game. There's no quit in our game. ... We have to get off to better starts. Thankfully, we're heading home for the next six games
playing Saturday. … Penguins forwards Sidney Crosby and Bryan Rust each had a point streak end. Crosby scored 10 points (three goals, seven assists) during a five-game streak, and Rust scored eight (five goals, three assists) during a six-game streak. … Forward Josh Bailey played his 901st game to pass Bob Nystrom for third in Islanders history behind Bryan Trottier (1,123) and Denis Potvin (1,060).