Washington goaltender Philipp Grubauer makes a save on Islanders center Casey Cizikas during Thursday’s 7-3 Capitals win, their third straight. (Kathy Willens/Associated Press)

Jaroslav Halak swung one leg and then the other over the bench wall as Christopher Gibson skated out of the New York Islanders’ net. The Washington Capitals watched and waited, grateful that it was the other team swapping goaltenders this time as the game started to get out of hand.

The Capitals picked apart the NHL’s worst defensive team, scoring five goals on their first 12 shots en route to a 7-3 win. Goaltender Philipp Grubauer, making his fourth straight start as typical No. 1 Braden Holtby continues his “reset” period, finished with 35 saves for his third straight win. It’s the first time Washington has won three straight games in more than two months.

“I thought tonight we did a great job,” forward T.J. Oshie said. “Obviously, as per usual here lately, it starts with Grubi back there.”

The Capitals host the Islanders on Friday in the second game of this home-and-home back-to-back set, and Holtby is scheduled to get his first start in more than a week. The 2016 Vezina Trophy winner was last in net March 6 in Anaheim, Calif., where he allowed three goals on the Ducks’ first nine shots before being pulled early in the second period, the third time he had been yanked from the net early in six starts. The team then turned to Grubauer to be the interim top goalie while Holtby took some time to work on his game.

But on Thursday night at Barclays Center, the Capitals benefited from the opposing team’s goaltending struggles. Capitals Coach Barry Trotz said he expected the game to have a playoff feel because the Islanders are desperate for points, presently on the outside of the postseason picture, and the contest was a shootout early. Against a New York team that has allowed a league-worst 3.51 goals per game, Washington scored three goals on nine shots in the first period.

“The Islanders just gave us a lot of room to skate on from the beginning,” forward Andre Burakovsky said. “I mean, my first three shifts, I was skating around and around and around with the puck and making plays. 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.”

The Islanders are also one of the NHL’s most talented offensive teams, and they opened the scoring. New York center Tanner Fritz skated around the back of the net, dishing the puck to the slot, where Brock Nelson scored with a point-blank shot on Grubauer 2:19 into the game. But then Washington tied the game when Lars Eller beat Gibson with a wrist shot from the right faceoff circle. That was Eller’s 16th goal, matching his career high set seven years ago with Montreal.

New York’s defensive lapses worked wonders for some of Washington’s forwards. Oshie had gone 19 games without a goal, and his last even-strength goal was Dec. 22 — 33 games ago. Oshie had been getting his chances lately, finishing with five shots on goal in Washington’s last game, but his drop in production from last season, when he scored a career-high 33 goals, has stung considering the 31-year-old signed an eight-year deal this past summer worth $5.75 million a year.

Before this game, Trotz reunited Oshie with center Nicklas Backstrom and Burakovsky, a trio that had been successful in the second round of the playoffs last season. Less than a minute after Eller’s goal, Oshie barreled toward Gibson on a two-on-one rush with Burakovsky. His 13th goal of the season lifted the Capitals to a 2-1 lead. Oshie also would score Washington’s seventh goal of the game, an empty-net tally.

“I actually bobbled [Burakovsky’s] pass a little bit, but it found the back of the net,” Oshie said of his first goal. “It was a great play by him. If that one didn’t go in, I don’t know. I don’t know what would’ve happened.”

The Islanders tied the game 60 seconds later, when Andrew Ladd scored on a rush with center Mathew Barzal. In an apparent theme for the evening, Ladd snapped a 25-game drought with the goal. But then defenseman Dmitry Orlov put the Capitals ahead again with his career-high ninth tally, turning Ladd inside out as he drove to the net and sneaked a puck past Gibson with a poor angle.

Washington didn’t turn back from there. The Burakovsky-Backstrom-Oshie trio got on the board once more when Burakovsky deflected a point shot from defenseman Jakub Jerabek in the second period. That ended a seven-game goal drought for Burakovsky and also was the first point with Washington for Jerabek, acquired just before the trade deadline. A power-play goal from Backstrom 10:22 into the second period prompted Halak off the bench to relieve Gibson.

“I thought it came easy for us today,” Trotz said. “. . . It was a little bit of luck going our way a little bit.”