UNIONDALE, N.Y. — In the Islanders’ first game back at Nassau Coliseum since their controversial fight-filled contest against the Penguins Friday, the Bruins issued a humbling beatdown to snap the Islanders season-high four-game winning streak Thursday night.

They employed no brutality in their decisive 6-3 win, just a well-balanced scoring attack against a complacent Islanders squad that came out flat.

Milan Lucic, Tyler Seguin, Blake Wheeler and David Krejci all finished with a goal and an assist apiece for the Bruins. Nathan Lawson coughed up five goals in his second start back from a sprained knee and backup Al Montoya made his second relief appearance in five days.

John Tavares scored two goals, the second of which cut the Bruins lead in half, 6-3, in the third, but the Islanders couldn’t make up for the ground lost in an abysmal first period.

“We came out slow. We didn’t play our game and we weren’t moving our feet off the bat,” Tavares said.

Trailing 3-0 after the first frame, the Islanders surrendered three more goals in the second. After letting up his fifth goal of the game_to Seguin at 2:48 — Nathan Lawson was yanked and replaced by backup Al Montoya.

Tavares and Josh Bailey combined for a pair of goals in the middle frame, but Milan Lucic’s power-play goal gave the Bruins a cushy four-goal lead going into the third.

Rookie Michael Grabner, who leads the team with 25 goals, was held off the scoresheet for the first time in seven games The Islanders four-game run was put in jeopardy early after an extremely disheveled first period in which they were outshot 15-4.

“That was the whole game,” said defenseman Milan Jurcina. “The first 10-15 minutes, that was crucial.”

The Bruins tallied three goals on seven shots against Lawson in the first 9:04 of the first period.

Wheeler threw the puck at the net with a pass intended to Michael Ryder for an early 1-0 lead at 1:52. Crashing the net, Mark Recchi scored the Bruins’ second goal when a puck hit his skate and caromed in at 7:03.

Lawson immediately went to argue the call, saying Recchi kicked it, but the goal was upheld after an official review.

Lawson gave up his third goal of the period when Gregory Campbell’s wrist shot from the blue line gave the Bruins a 3-0 lead at 9:04.

Zenon Konopka dropped the gloves against Bruins defenseman Adam McQuaid shortly after the Bruins first goal.

Easily the most vocal Islander in the wake of Friday’s mayhem and the suspensions that followed, Konopka voiced his displeasure again.

From the penalty box, Konopka was barking toward on-ice officials after receiving a two-minute minor for unsportsmanlike conduct in addition to his fighting major.

“He told me it was pre-meditated, and I said I disagreed,” Konopka said.

Micheal Haley, who fought three different Penguins Friday including Max Talbot and goaltender Brent Johnson, was slapped with a 10-minute misconduct after repeatedly challenging Bruins’ Gregory Campbell to fight. Campbell is the son of league disciplinarian Colin Campbell.

“We were doing nothing that we normally do,” Jack Capuano said. “For whatever reason we didn’t come out focused or ready to play.”