Barzal was playing his first game since Dec. 11 (missed three games) because of COVID-19 protocol.
"I think he's obviously a big part of our game," said Islanders defenseman Noah Dobson, who had a goal and an assist. "To see him back, he was flying around tonight. … I think it's nice when guys are out for a little bit and we get them back. They definitely bring an energy to the team, and I think you saw that tonight."
Kieffer Bellows had a goal and an assist, and Semyon Varlamov made 36 saves for the Islanders (9-12-6), who had not played since Dec. 19.
Kyle Okposo scored, and Malcolm Subban made 28 saves for the Sabres (10-17-5), who were coming off a 4-3 loss to the New Jersey Devils on Wednesday.
"To start the game, we were just making little mistakes that we don't usually make," Okposo said. "Our puck management, I turned one over in the middle of the ice. … So I'll take responsibility for that start to the game, and I just think we didn't manage it well enough through the neutral zone, especially, and entering their zone. Their gaps were really good. They have great sticks. They got a lot of sticks on pucks and we didn't make clean plays. When you're not doing that, you just got to get it behind them and play simple. We just didn't do that tonight. … Call it whatever you want … we didn't mentally make the correct decisions at all tonight."