NEW YORK -- When the Buffalo Sabres lost starting goaltender Robin Lehner to an ankle injury in the first week of the season, there was speculation they might acquire another goalie to ease the blow.
But the Sabres weren't interested. They viewed it as an opportunity to see what they had in Linus Ullmark.
So far, they like what they see.
Ullmark made 29 saves to lift the Sabres to a 2-1 win against the New York Islanders at Barclays Center on Sunday.
Rookie Sam Reinhart broke a tie when he scored the game-winning goal with 6:16 remaining.
Matt Moulson scored for the Sabres (5-7-0), who won back-to-back games for the first time this season thanks in part to the play of their 22-year-old goaltender. Ullmark, who had hip surgery last spring, has allowed two goals on 58 shots over the stretch.
"He's coming off his injury and rehab, and we liked a lot of what we saw from him in training camp, be it not involved in scrimmages or not involved in games," Sabres coach Dan Bylsma said. "We really wanted to see him play some games and play some North American games, which he did in Rochester. The three games he played there, he was the best player on the ice."
Reinhart gave the Sabres their first lead of the game when he redirected David Legwand's feed past Islanders goalie Thomas Greiss for his second goal at 13:44 of the third period.
"There wasn't much room to pass it across, and he really fired it," Reinhart said. "It was a great play. A lot of credit to [Legwand]."
Defenseman Calvin de Haan scored for the Islanders (6-3-3), who played a second straight game without captain John Tavares because of flu-like symptoms. Greiss made 20 saves.
New York is 0-1-2 in its past three games.
"We're not going to cut the excuses," Islanders defenseman Travis Hamonic said. "There's obviously guys who are going to be in and out of the lineup throughout the whole season. Can't anticipate those things. John's one of the best players in the world, certainly, so you're going to miss him. Show me a team that's [not] going to miss their best player and one of the best in the world, and I'll say they're lying. We want him out there with us, but we have to duck, everyone has to pick up their own socks and have a better effort.
"You're not going to replace what Johnny brings every night. Certainly, everybody has to up their effort."
After a scoreless first period, de Haan got the Islanders on the board with his first goal of the season 13:42 into the second. With the teams at even strength and the Islanders pressuring, de Haan received a pass from Cal Clutterbuck and beat Ullmark with a shot through traffic from the slot to give New York a 1-0 lead.
Greiss preserved the lead with his biggest save of the game less than three minutes later when he got his left pad on Moulson's backhand shot after a bad line change by the Islanders allowed Moulson to get sent in on a breakaway.
Kyle Okposo nearly doubled the lead for New York one minute into the third period when he took one stride over the blue line and ripped a slap shot that got past Ullmark but hit the far goal post.
"Frustrating," Okposo said. "We want to perform."
Buffalo tied it at 6:20 of the third when Moulson scored his fourth goal. Moulson, a former Islanders forward who was celebrating his 32nd birthday, took a cross-ice feed from Zemgus Girgensons and poked it past Greiss to make it 1-1.
"When the trade happened, obviously it's an emotional thing just because of the love I had for the team and the organization and the people and the guys on the team," said Moulson, who had three 30-goal seasons for the Islanders before being traded to Buffalo for Thomas Vanek on Oct. 27, 2013. "Obviously, it's a business. It's emotional. People have feelings, they're still humans. But there's no grudges. I don't think that's good for anyone. There's still a lot of good friends over there and a lot of great people."
Ullmark prevented the Islanders from regaining the lead with 9:56 remaining when he managed to get across the crease to deny Steve Bernier's one-timer from point-blank range after a feed from the corner by Mikhail Grabovski.
"I think just as a team, we've become better and better," Ullmark said. "We buy in every day. It's not me that's making the difference; it's the team that's making the difference every game and every night. We have great confidence in our style."
Neither team was penalized in the game.
"I don't know if I've seen a perfect score sheet like that, no penalties for and against, but the referees … I don't think there was much out there for the refs to call," Bylsma said. "But it doesn't happen very often."
Sabres center Tyler Ennis returned to the lineup after missing the previous two games because of a lower-body injury.