Their coach wasn’t pleased, but the Islanders’ 5-2 takedown of the Pacific Division-leading Los Angeles Kings on Thursday night at Barclays Center still felt like a benchmark victory for an Isles team that’s been floating along the past two months.

As they did against the cellar-dwelling Oilers on Sunday, the Islanders jumped out with three first-period goals, again sparked by a long-range slapper from Johnny Boychuk in the game’s opening minutes.

The Kings put up more of a fight than Edmonton did, but the Islanders did enough to keep Los Angeles at bay and win their third straight to move 11 games over .500 (29-18-6) for the first time this season.

“They’re an unbelievable team,” said Casey Cizikas, who put a rebound past Jhonas Enroth for a 2-0 lead at 11:19 before Anders Lee scored a power-play goal 2:27 later. “They’ve got size, skill, grit. For us to come out the way we did, it’s big for our club moving forward.”

As is the increased production from John Tavares, who set up Boychuk’s ripper 6:05 into the game and then scored a key goal off a two-on-one at 13:30 of the second period to restore a three-goal lead.

advertisement | advertise on newsday

The Kings cut the Isles’ lead to 4-2 in the third period on Milan Lucic’s rebound goal with 10:09 to go, but Travis Hamonic hit the empty net with 3:25 left to seal it.

This was the last Barclays Center visit from a Western Conference team this season, and the Islanders will be sad to see those squads go. They finished 12-0-2 against the West at home.

But Jack Capuano wasn’t happy after the win, believing his team turned in a sloppy performance after taking the 3-0 lead through 20 minutes.

“You just can’t mismanage the puck like we did here tonight,” Capuano said. “In the second and third, it just looked like some guys weren’t moving their feet.”

Thomas Greiss made 28 saves though he, too, said he wasn’t at his best. The Kings had a 69-53 edge in shot attempts and Greiss credited his teammates for helping get his 15th win of the season in his 22nd start. It was even more impressive, given that the Kings scored nine goals against the Bruins in Boston two nights earlier.

“The team played great today in front of me, getting five goals when I didn’t think I was at my best,” Greiss said. “Even if they didn’t score nine the game before, it’s a championship team. It’s a great win.”

Tavares’ two points gave him 12 in the last seven games, and he’s scoring at key moments.

Kyle Clifford broke through on Greiss at 11:10 of the second, capping a long stretch of dominant play for the Kings.

But Ryan Strome’s neat chip in the neutral zone sprung Tavares, whose wrist shot went off Enroth’s shoulder and in for his seventh straight 20-goal season.

“He’s working hard. He works hard every day,” Capuano said. “He’s getting the same chances he was getting a month and a half ago that weren’t going in.”

advertisement | advertise on newsday

The Islanders head to Raleigh for Saturday’s game against the Hurricanes, who are bobbing below the playoff cut line, before home dates against the Red Wings and Capitals next week.

Despite Capuano’s disappointment, the victory might be the one that reminds the Isles how they need to play against the NHL’s elite.

“I think we’re a confident team in here right now,” Cizikas said. “We all know what we’re capable of.”