NEW YORK — Shea Weber scored a power-play goal at 17:03 of the third period to snap a 2-2 tie as the Canadiens defeated the New York Islanders 3-2 Wednesday night at Barclays Center. Weber’s third goal of the season came off Montreal’s only power play of the night and came against the No. 1 penalty-killing team in the NHL. He beat Thomas Greiss with a slapshot as the Canadiens improved to 6-0-1 on the season. Al Montoya picked up the win and improved his record to 3-0-1.

Tit-for-tat: Philip Danault gave the Canadiens a 2-1 lead when he scored at 11:21 of the third period. Greiss made a save on Torrey Mitchell but Danault tucked the rebound inside the post. But the Islanders tied the game for the second time when Dennis Seidenberg scored on a shot from the point through traffic at 14:16.

Net presence pays off: Paul Byron gave the Canadiens a 1-0 lead when he scored his second goal of the season at 3:10 of the second period. Islanders defenceman Nick Leddy managed to get his stick on Alexei Emelin’s shot from the faceoff circle but the puck trickled through and Byron scored on the rebound after Greiss stopped Brendan Gallagher.

Tavares ties it up: Artturi Lehkonen took the first penalty of the game when he was called for high-sticking at 14:42 of the second period and the Islanders cashed in 35 seconds later when John Tavares scored an unassisted goal after Emelin failed to clear the puck. He used teammate Andrew Ladd as a screen, shooting through Ladd’s legs. It was Tavares’s fourth goal of the season.

Greiss keeps it close: The backup goaltender was outstanding in the second period when he made big stops on Gallagher, Max Pacioretty and Brian Flynn. He also had the hockey gods on his side six minutes into the third period when Galchenyuk hit the crossbar.

Beauvillier injured: Islanders winger Anthony Beauvillier left the game late in the second period after he was struck in the head by a shot from Greg Pateryn. He returned in the third period.

Halak gets night off: The Islanders elected not to dress former Canadiens goaltender Jaroslav Halak, who has a 4-2 record against Montreal. Greiss got the start with Jean-François Bérubé as the backup.

What’s next: The Canadiens return to the Bell Centre to face the Tampa Bay Lightning (7:30 p.m., Sportsnet 360, RDS, TSN Radio 690) in a battle for first place in the Atlantic Division. The Canadiens are currently three points up on the Lightning but Tampa Bay has a game in hand. This is the start of a three-game homestand. Auston Matthews and the Toronto Maple Leafs are in town Saturday followed by the Vancouver Canucks Wednesday.