The Washington Capitals were chasing from the drop of the puck Monday night against the New York Islanders. With turnovers aplenty, a lack of physicality and breakdowns all over the ice, the Capitals struggled for the second straight game and lost, 5-3, at Capital One Arena.

The final score was relatively close after the Capitals turned up the energy late in the second period and for the entirety of the third, but costly, self-inflicted errors dominated the night, and Washington didn’t come close to resembling the powerful outfit it has been for the majority of the season.

“It’s too easy to score against us right now,” center Lars Eller said.

“It’s not because of our goalies. It’s because we’re losing races, we’re not winning battles in front of the net, we’re not boxing out. So whether it’s tips or it’s two-on-ones or three-on-twos, we’re getting beat just a couple feet.”

The Capitals (36-15-5) are now under .500 (3-4-0) since the all-star break and a middling 10-9-0 beginning with a 7-3 loss to the Boston Bruins on Dec. 23. Washington has allowed four or more goals in 10 of its 19 games in that span, and much of Monday’s loss felt like a continuation of Saturday’s disappointing effort in a 7-2 home loss against the Philadelphia Flyers.

“We’re going through a tough stretch right now,” Coach Todd Reirden said. “We’re losing those battles. We’re making poor decisions with the puck, making some mental mistakes, and they’re ending up in our net. We’re finding ways to lose right now, whereas before we were finding ways to win.”

While multiple areas of the Capitals’ play are concerning as the postseason creeps closer, a new worry Monday night was the health status of center Evgeny Kuznetsov.

The dynamic Russian left the ice in pain in the middle of the second period after taking a big hit from Islanders center Leo Komarov along the boards. Kuznetsov suffered an upper-body injury and did not return, and Reirden said he will be reevaluated Tuesday.

“I think, if you look at the past, every time one of our key players has been out, the whole team steps up and we can get the job done,” Eller said. “But hopefully he’ll be back soon, and we’re going to be better when he’s back.”

The Capitals were trailing 4-1 at the time of Kuznetsov’s injury, and the night went from bad to worse in a matter of minutes. Jordan Eberle widened the ­Islanders’ lead to four goals at 10:36 of the second period when he drove to the net and put the puck past Capitals rookie goaltender Ilya Samsonov, who was then pulled and replaced by Braden Holtby.

Samsonov matched a career high by allowing five goals on 20 shots, though more than one of them were the result of clear defensive errors in front of him that led to opportune chances for the Islanders.

“It’s always tough when it’s your first time going through something like that,” said Holtby, who stopped all 12 shots he faced. “The thing is, he had no chance — it was just stacked against him.”

The hosts finally started to regain some of their composure and project a semblance of their typical game after the goalie switch. Eller scored his 14th goal of the season from the front of the net less than a minute after Samsonov left to make it 5-2, and T.J. Oshie scored his 21st goal from Alex Ovechkin’s typical spot on the power play to make it 5-3 with 3:01 left in the period.

Ovechkin, who remains two goals shy of becoming the eighth NHL player to score 700 in his career, came up empty for the second straight game despite putting six shots on goal. He was on the ice for all five Islanders goals and finished minus-4 in a poor defensive showing.

Ovechkin’s next chance at 700 will come Thursday, when the Capitals visit the Colorado Avalanche for the start of a three-game road trip.

“These are not fun times,” Reirden said, “but they’re times that you need to realize, assess properly, come up with a plan and work forward.”

It briefly appeared that Ovechkin had scored No. 699 late in the first period, when the Capitals already trailed 2-0. Defenseman John Carlson took a shot from the point that seemed to deflect off Ovechkin in front of the net and past Islanders goaltender Thomas Greiss.

Replays showed, however, that Carlson’s shot had deflected off Islanders defenseman Johnny Boychuk’s skate and had not touched Ovechkin. Carlson was credited with his career ­high-tying 15th goal of the season instead.

Aside from those dramatics 12:55 into the game, the early stages belonged to the Islanders.

Anthony Beauvillier took advantage of two defensive lapses by the Capitals and scored twice in less than three minutes to give New York its initial two-goal lead. The first goal came 3:30 into the game on a three-on-two rush, and his second came when he got to a rebound right in front of the net at 6:16.

The rebound opportunity came at the end of a sequence that included a turnover by Capitals defenseman Martin Fehervary, who was in the lineup for the third straight game. The Capitals have wanted to see more of their young defenseman and take inventory as the trade deadline approaches, so they decided to sit Jonas Siegenthaler, Nick Jensen and Radko Gudas for one game each over the past week and insert Fehervary in their place.

Gudas was the healthy scratch on the blue line Monday, and Fehervary started on the second pair with Dmitry Orlov for the second straight game. Fehervary finished a minus-3, the worst mark among Capitals defensemen.

The Capitals eventually got straightened out, holding the Islanders scoreless for more than 29 minutes to end the game, but by then they trailed by four and had too much to overcome.

“Got plenty of offensive-zone time tonight, but then when we do have to defend, we’ve got to be harder around our net,” Reirden said.

“We’ve got to do a better job in coming into D-zone to sort out our responsibilities.”

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