Washington trailed by three goals late in the second period, but Alex Ovechkin and the Capitals roared back for a 5-4 shootout win on Tuesday night.
Ovechkin scored in the final minute of the second to make it 4-2 and start the comeback. Dmitry Orlov scored 1:51 into the third, and Ovechkin made it 4-4 with his 29th goal midway through the period when he knocked a rebound of Keith Aucoin's slap shot past goalie Evgeni Nabokov. Aucoin had a career-high three assists.
The Capitals (36-28-6) have won four straight and lead ninth-place Buffalo by four points in the Eastern Conference playoff race. The Capitals, 13-18-3 on the road, are only one point behind the Southeast Division-leading Florida Panthers.
"It's the playoffs for us right now," Ovechkin said. "Teams are fighting for those spots, and we need these points."
John Tavares scored twice for the Islanders, including his career-best 30th goal, and added an assist, Matt Moulson netted his 30th of the season, and defenseman Travis Hamonic also scored for the Islanders (28-31-11), who lost their third straight game in heartbreaking fashion.
"We've got to be better when we have a lead," Tavares said. "It's hard to pinpoint the problem, but that's three games in a row."
Moulson gave New York a 1-0 lead 8:54 in when his slap shot deflected off the glass behind the net and then dropped in by goalie Michal Neuvirth. Moulson has scored 30 goals in three consecutive seasons, the first time an Islanders player has done that since Ziggy Palffy (1996-98).
Hamonic's power-play tally, his second goal of the season, from Tavares and Frans Nielsen at 19:39, made it 2-0. Tavares scored at 9:05 of the second on the power play to push the lead to three. Hamonic also had two assists for his first three-point game in the NHL.
Mike Knuble scored his fourth goal of the season 28 seconds later to bring the Capitals within 3-1.
Tavares scored his second of the game at 11:44 of the second period with a snap shot from the right circle to beat Neuvirth, who still managed to improve to 5-0 against the Islanders.
"It wasn't going my way early, but I battle every minute for every save, and it paid off," Neuvirth said. "That was an unbelievable comeback and a huge win for us."
Capitals coach Dale Hunter was impressed with his team's grit and leadership.
"We have good leaders on this team, and they got us back in the game," said Hunter, who replaced Bruce Boudreau on Nov. 28. "We were on our heels and down 4-1 but the guys didn't give up. They busted their tails and got a big win."
New York won the first two meetings with the Capitals and were leading 2-0 in the third matchup on Feb. 28 with less than four minutes left in regulation. But Troy Brouwer scored twice, and Ovechkin won it in overtime.
The Capitals began a five-game trip as they try to improve their playoff positioning. Since Feb. 18, Washington had lost three straight, won three in a row, and lost another three consecutively before this three-game winning streak.
The Islanders' back-to-back losses over the weekend were particularly demoralizing. This latest loss added to the pain.
"Our discipline and decision-making is what bothers me," Islanders coach Jack Capuano said. "You have to know who you're up against. We talked about Ovechkin, and still he was able to get a couple to the back of our net."
Islanders RW P.A. Parenteau sat out because of an undisclosed upper body injury. ... The Capitals were without forward Nicklas Backstrom (concussion) and defenseman Tom Poti (back). Defenseman Mike Green served the last of a three-game suspension. ... The three points for the 21-year-old Tavares left him one point shy of becoming the first Islanders player to have at least 70 in a season since Alexei Yashin had 75 in 2001-02.