Andrew Ladd and Anders Lee scored 43 seconds apart early in the third period to lift the Islanders over the Washington Capitals 4-3 on Tuesday night.
Ladd had two goals and Cal Clutterbuck added another for New York, which improved to 14-14-6 overall and 11-7-4 at home.
Jaroslav Halak stopped 31 of 34 shots for the Islanders.
Despite getting goals from Justin Williams, Alex Ovechkin and Andre Burakovsky, Washington fell to 20-9-4 with its third loss in four games. Braden Holtby stopped 27 shots.
New York never trailed in the third meeting this month between the longtime rivals.
Still it took a 1-2 combination from Ladd and Lee to put New York in position to win its third straight game.
Ladd broke a 2-2 tie 4:41 into the third by shoveling Alan Quine's pass into the net. Signed to a seven-year, $38.5 million free agent contract on July 1, Ladd scored two goals in a game for the first time as an Islander.
Lee followed with a breakaway score at 5:24 to give New York a two-goal lead. Lee snapped a wrist shot that beat Holtby cleanly after the wing corralled defenseman Matt Niskanen's turnover at the Islanders' blue line.
Burakovsky cut the deficit to 4-3 with his fourth goal of the season with 6:55 left. After Burakovsky's goal, New York had to kill two minor penalties to close up shop. The Islanders killed all four Washington power plays for the game.
Ovechkin opened the third period by scoring on a backhander at 1:17 to tie it at 2.
Ladd's sixth goal gave the Islanders their second lead of the game, 2-1, at the 14:03 mark of the second. Stationed at the far post, Ladd was able to tap in Thomas Hickey's shot from the left side.
New York took a 1-0 lead 8:02 into the game on Clutterbuck's third of the season, his first since Nov. 7, and the 99th of his NHL career. The goal was the culmination of a sequence which began on Nikolay Kulemin's rush up the left wing boards. Kulemin fired a shot that Holtby couldn't control and Clutterbuck jabbed the rebound into the net.
Williams tied it 5:22 later by poking a rebound of Ovechkin's shot past Halak. After the goal, Halak appeared to complain that he had been interfered with by Williams.
Williams was called for goaltender interference midway through the second period after colliding with Halak behind the New York net.