Anders Lee, Casey Cizikas and Cal Clutterbuck scored, and Ilya Sorokin made 24 saves to give the Islanders (15-6-4) an eight-game point streak (7-0-1). They are the only team in the NHL without a regulation loss at home (10-0-2).
"Coming into our home building, this is our ice, this is our home," Cizikas said. "We want to put our best games forward and make it hard on the other teams, knowing that when they come here, it's going to be a dogfight. We've done that so far at the start of the season."
New York completed a three-game sweep of Buffalo, winning each game 5-2.
"You see them three times in a row, all in our building, it's a miniseries," Lee said. "That third game's tough, especially on a back-to-back. We knew that coming in and I think we just did a really good job of sticking to our game."