Beauvillier won it with a wrist shot from the right face-off circle after a turnover by Blake Coleman. It was Beauvillier's first goal in 11 games, fifth of the 2021 Stanley Cup Playoffs and first in overtime in the NHL postseason.
"I honestly kind of blacked out a little bit," Beauvillier said. "They turned the puck over, I think, and then I saw it go in and kind of blacked out. I was just so happy, I was screaming, and everyone kind of jumped on me. Obviously, an amazing feeling and I couldn't be more happy."
Scott Mayfield tied the game at 11:16 of the third period for the Islanders. Semyon Varlamov made 22 saves.
"I love this group, the character of this group, and I would say this building and what it's meant to a number of players, but probably more than anything, our fans," New York coach Barry Trotz said.