Matt Hendricks beats Islanders goalie Evgeni Nabokov for the shootout winner. (Bruce Bennett/Getty Images)

It took about 40 minutes, but the Washington Capitals finally played with the kind desperation one would expect from a team clinging to the Eastern Conference’s final playoff position.

It also didn’t hurt that the New York Islanders are the worst team in the league when it comes to defending a late lead.

Alex Ovechkin scored twice in regulation to help rally the Capitals from a three-goal deficit, and Matt Hendricks tallied the decisive goal in the shootout to clinch a 5-4 victory that extended Washington’s winning streak to four games.

The scuffling Islanders fell to 15-1-8 when leading after 40 minutes Tuesday at Nassau Coliseum, while the Capitals improved to 2-3 in games decided by shootout.

“We take a lot of positives out of it,” said Mike Knuble, whose second-period tally was his first since Dec. 5. “We didn’t start out well but we didn’t quit. We got the two points and that’s the biggest thing, to keep putting pressure on Florida and Winnipeg.”

New York's Travis Hamonic is checked by the Capitals' Alex Ovechkin (8) during the first period. (Paul Bereswill/Associated Press)

The win helped the Capitals (36-28-6, 78 points) remain a point behind Southeast Division-leading Florida, which thumped Toronto 5-2, and also stretched their lead over Buffalo to four points.

“It’s a good sign for us we didn’t stop playing and we come back,” Ovechkin said. “It’s playoffs for us right now and teams who fight for that kind of spot. It’s a huge win for us. We need those points.”

The third period began with the Islanders (28-31-11) leading 4-2, and just 1 minute 51 seconds in, the comeback commenced on a goal by defenseman Dmitry Orlov, who pinched and finished a pass from Marcus Johansson (two assists) with a slick deke of Evgeni Nabokov (24 saves).

About eight minutes later, Ovechkin’s second goal of the night, scored when he flipped his own rebound into the net, knotted the game, 4-4. Minor league call-up Keith Aucoin got the assist on the goal and notched his first career three-point game.

“Awesome for him,” Hunter said of Aucoin. “He’s a really good playmaker. He's a creative guy, and he put numbers up in the American League and he’s doing very good for us.”

Michal Neuvirth (26 saves) made a key stop on Josh Bailey in overtime, then Ovechkin and Hendricks beat Nabokov in the shootout.

“I was shocked too,” Ovechkin said jokingly about his nifty move. “I didn’t know I had that kind of skill.”

Alex Ovechkin of the Washington Capitals ties the score at 4-4 at 10:15 of the third period. (Bruce Bennett/GETTY IMAGES)

But the Capitals’ chances didn’t always look so good.

Playing before a half-filled building, against an opponent that had lost three in a row and was playing without its second leading scorer in PA Parenteau, they had inexplicably sluggish start given their tenuous grasp on a playoff spot.

The Islanders’ first goal, credited to Matt Moulson, was of the blooper-reel type. After Moulson’s slap shot hit the end glass, it ricocheted back over the net, where it hit Neuvirth in the chest and dribbled into the net before the goaltender could corral it with his glove.

Then, with only 21 seconds remaining in the opening frame, Travis Hamonic gave the Islanders a two goal edge with another bad break goal. Hamonic’s power play crossing pass deflected off Washington defenseman John Carlson’s skate and past Neuvirth.

In the first period, the Capitals mustered only four shots — two by Jason Chimera and two by Johansson.

By the midpoint of the second period, the first of John Tavares’s two goals, had the Islanders ahead 3-0.

“We needed to kind of pull our head out of somewhere dark, to say the least,” Hendricks said. “The coaches said a little bit of something [after the second period]. But I think it was the leaders in this room that spoke up.”

“And then,” he added, “Ovi was a force tonight with two goals and a big shootout goal for us.”

Indeed he was.

Ovechkin’s first goal came on a rebound with 53 seconds remaining in the second period and put the Capitals in striking distance, 4-2.

“We need guys to step up and score goals,” Coach Dale Hunter said. “Tavares was having a heck of a game out there. So we had to match him somehow and we stepped up.”