NEW YORK -- Tomas Nosek broke a tie 3:32 into the third period, and the Vegas Golden Knights defeated the New York Islanders 3-2 at Barclays Center on Wednesday.
Jonathan Marchessault and William Karlsson also scored for Vegas (18-14-1), which opened a four-game Eastern Conference road trip with its ninth victory in its past 11 games. Marc-Andre Fleury made 23 saves.
"A road win for sure tonight," Nosek said. "It wasn't our best game, it wasn't our worst game. It's great to have a win like that on the road."
[WATCH: All Golden Knights vs. Islanders highlights]
Mathew Barzal had two assists, and Robin Lehner made 14 saves for New York (14-12-4), which has lost two games in a row and four of five.
"A missed opportunity," Islanders coach Barry Trotz said. "We played well in so many areas of the game, but we gave them things that were a little bit unforced.
"Turnovers cost us. I thought we held a pretty good hockey team that's been really hot to 17 shots. You feel you can get a point out of that."
Vegas took a 1-0 lead 34 seconds into the game on Marchessault's power-play goal. Fifteen seconds after Casey Cizikas was whistled for high sticking, Marchessault took a pass from Colin Miller and beat Lehner with a wrist shot from the right face-off circle.
Video: VGK@NYI: Marchessault opens scoring with PPG
The Islanders quickly responded when Johnny Boychuk skated with the puck behind the Golden Knights net and fed Anthony Beauvillier in front for a one-timer to tie it 1-1 at 3:17.
Adam Pelech gave the Islanders a 2-1 lead at 11:19 of the second period when he sent a wrist shot past Fleury after a drop pass from Barzal from the left circle.
"I think Mathew's game has been building," Trotz said of Barzal, who has four assists during a three-game point streak. "Last three games he's put together have been really solid. I think he's working on both ends, he's been dangerous, he's becoming more complete. I want to play the [heck] out of him when he does that. That's exciting for us."
Video: VGK@NYI: Beauvillier taps home Boychuk's pass
Karlsson tied it 2-2 at 16:31 when he intercepted Nick Leddy's clearing attempt from behind the net and beat Lehner with a wrist shot from the right circle. It was Karlsson's 11th goal and sixth in his past nine games.
"Good road win," Karlsson said. "They made it tough on us to get in front of the net. They did a real good job defensively."
Video: VGK@NYI: Karlsson wires wrist shot past Lehner
Nosek scored the game-winner with 16:28 remaining. Lehner made the initial save on Oscar Lindberg's shot from the left circle after Ryan Pulock turned over the puck deep in the Islanders zone, but a miscommunication between Hickey and Lehner allowed Nosek to swat the rebound over the goal line to give the Golden Knights a 3-2 lead.
"We talked it out," Hickey said. "It looks easy, it looks like it's there, but there's blind spots for the goalie and you're trying to communicate and wanting him to cover it. He couldn't see it; he didn't know where it was. It's on the both of us to communicate and get it out of harm.
"It's one of those things that it looks simple, but there's blind spots out there for everyone. Split-second things."
They said it
"It didn't seem like we had a ton of shots. [Marc-Andre] Fleury made some big saves for us. We just capitalized on some chances. Starting the road trip off like this definitely feels good. It gives us some confidence." -- Golden Knights forward Ryan Carpenter
"We've got to find a way to win these games against good hockey teams and not giving them too much quality wise. They just find a way, and we're the team that needs to find a way to win those." -- Islanders defenseman Thomas Hickey
Need to know
The start of the third period was delayed by 16 minutes because of a power issue. … The Islanders were the only team the Golden Knights had not defeated since entering the NHL last season. … Each team had one power play. … Fleury has won 10 of his past 12 starts. He has 422 NHL wins, one shy of Tony Esposito for ninth in history. … Vegas center Paul Stastny practiced Tuesday but missed his 30th consecutive game because of a lower-body injury. … Beauvillier has scored in back-to-back games. … Islanders forward Leo Komarov was able to play after missing the morning skate with soreness. Forward Joshua Ho-Sang was a healthy scratch.
Golden Knights: At the New Jersey Devils on Friday (7 p.m. ET; MSG+, ATTSN-RM, NHL.TV)
Islanders: Host the Detroit Red Wings on Saturday (Nassau Coliseum; 7 p.m. ET; MSG+, FS-D+, NHL.TV)
Video: Nosek's go-ahead goal leads Golden Knights to 3-2 win