Matt Niskanen scored two goals in the third period, lifting the Washington Capitals over the Islanders 4-2 on Tuesday night for their fifth straight victory.
Brett Connolly and Justin Williams also scored for Washington, which improved to 18-7-3. Dating to a 2-1 overtime loss at Tampa Bay, the Capitals have earned 11 out of a possible 12 points.
Following a five-game winning streak, the Islanders have dropped their last two. New York's 11-12-5 record is the worst in the Metropolitan Division.
Brock Nelson and Nikolay Kulemin scored for the Islanders, and Jaroslav Halak made 34 saves.
The third meeting of the season between the teams - and second in 12 days - was a tight-checking game. Neither team was able to sustain sequences in the offensive zone, though the Capitals finished with a 38-25 advantage in shots on goal.
Niskanen's wrister from the right circle 1:34 into the third was the game's biggest shot, as it put Washington ahead for good. The defenseman snapped a feed from partner Dmitry Orlov, as all five Islanders were on the left side of the ice.
From there, Braden Holtby made the lead hold up.
Holtby stopped 36 shots, with his two toughest saves coming on Josh Bailey's goal-mouth backhander with 11 minutes left and John Tavares' snap shot from the slot nearly 2 minutes later as the Capitals held onto their one-goal lead.
Niskanen's power-play goal with 1:57 left ended the scoring.
Trailing 1-0 after the first period, it took the Capitals all of 2:09 to draw even on Connolly's third of the season. A scratch in Washington's previous four games, Connolly drove to the net and Lars Eller's centering pass ricocheted off his stick blade.
Washington went ahead 5:28 later on Williams' power-play goal. Jakub Vrana drove to the net and Evgeny Kuznetsov, who was behind the goal line, found him with a pass, and the 20-year-old's shot bounced off Williams.
The Capitals finished 2 for 3 on the man advantage, and killed off both New York power plays.
Despite being outplayed for much of the period, New York was able to tie the game at 2 on Kulemin's goal midway through the second. Kulemin deflected Nick Leddy's point shot past Holtby for his third of the season.
Halak made certain the game stayed tied going into intermission, as he made stops in the final minute on Karl Alzner, Alex Ovechkin and Niskanen, prompting the crowd of 12,730 to chant his name.
New York struck first on Nelson's seventh of the season at 9:32. The left wing was sprung by Cal Clutterbuck's stretch pass, and Nelson fired an end-over-end shot from the top of the left circle that beat Holtby over his glove.
The goal was Nelson's first since Dec. 1.
NOTES: The Islanders returned D Scott Mayfield to Bridgeport of the AHL. Mayfield had one goal and two assists in three games. . Washington scratched D Taylor Chorney and LW Andre Burakovsky, while the Islanders scratched J.F. Berube and Alan Quine. . New York C Casey Cizikas missed two first-period shifts after taking a skate blade to the wrist during his first shift of the game. ... The Metropolitan Division rivals will meet twice more this season on Dec. 27 and Jan. 31, both in New York.
Capitals: Play at Carolina on Friday night.
Islanders: Host the Chicago Blackhawks on Thursday night.