Islanders defenseman Johnny Boychuk and teammates skate off the ice...

Islanders defenseman Johnny Boychuk and teammates skate off the ice after a loss to the Capitals at Barclays Center on Thursday. Credit: Kathleen Malone-Van Dyke

WASHINGTON — The Islanders need to shore up their defensive effort as they conclude a home-and-home series with the Capitals on Friday night at Capital One Arena.

And that’s not just because the Capitals won, 7-3, on Thursday night at Barclays Center as they chased Christopher Gibson after the goalie allowed five goals on 12 shots. Or that the Islanders allowed five or more goals for the 19th time this season.

It has more to do with the open space the Capitals found for skating room.

“The Islanders just gave us a lot of room to skate on from the beginning,” said Capitals left wing Andre Burakovsky, who made it 4-2 at 3:12 of the second period after setting up T.J. Oshie’s goal to make it 2-1 at 11:29 of the first period.

“I mean, my first three shifts I was skating around and around and around with the puck and making plays,” Burakovsky added. “I mean, we didn’t really expect that out of them. We were expecting a little bit harder pressure when we had the puck. But, yeah, they just gave us a lot of ice to skate on.”

Perhaps it’s not the greatest example since the game was long decided, but John Carlson’s goal to make it 6-2 at 15:41 of the third period was a prime illustration.

Skating against a forward trio of center Mathew Barzal, Jordan Eberle and Russ Johnston and the defense pair of Johnny Boychuk and Nick Leddy, Carlson skated unhindered from the blue line on in until he found a spot to beat goalie Jaroslav Halak.

Halak relieved Gibson, who has started four of the past five games, at 10:22 of the second period and the Islanders trailing 5-2. Halak stopped eight of nine shots he faced. The Islanders outshot the Capitals, 12-5, in the third period. Halak is the likely starter on Friday night.

Embattled Capitals coach Barry Trotz is likely to turn to Braden Holtby after Philipp Grubauer made 35 saves on Thursday night.

Either way, the Islanders must do a better job of creating traffic at the Capitals’ crease.

“They do a great job of keeping you out of the goalie’s eyes and we’ve got to do a better job of that,” Islanders coach Doug Weight said.

The Islanders (30-30-10) remain in last place in the Metropolitan Division, 10 points behind the Devils for the Eastern Conference’s second wild-card spot. In other words, they are a near lock to miss the playoffs for the second straight season after winning their first playoff series since 1993 in 2016.

The Capitals (40-23-7) are in first place in the Metropolitan Division, tied with the Penguins with 87 points but having played two fewer games than the two-time defending Stanley Cup champions.

Thursday night’s victory gave the Capitals a three-game winning streak for the first time since they won five in a row from Dec. 28-Jan. 9.

Despite the latest defeat — and the Islanders had just snapped an 0-4-4 skid with Sunday’s 5-2 win at Calgary — there were a handful of positives.

Barzal, a leading candidate for the Calder Trophy, reached 70 points by setting up Andrew Ladd’s goal to tie the score at 2 at 12:29 of the second period. Barzal became the first rookie in the NHL to reach 70 points this season and he now has one more point than the Maple Leafs’ Auston Matthews finished with last season when he won the Calder.

Ladd snapped a 25-game goal-less streak dating to Dec. 21.

The 32-year-old left wing, in the second season of a seven-year, $38.5 million deal, now has 10 goals and 13 assists in 61 games.

“It is what it is,” Ladd said. “Obviously no one wants to go through a stretch like that. You try different things to get yourself going, try shooting the puck and just getting things to the net.”

Lastly, defenseman Ryan Pulock had a goal — cutting the Capitals’ lead to 6-3 at 16:33 of the third period — and an assist and is now second among NHL rookie defensemen with seven goals and fourth with 23 points.

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