Elias Lindholm also scored for the Bruins, who are the first wild card from the Eastern Conference. Jeremy Swayman, who was pulled in the third period of a 6-1 loss in Game 4, made 24 saves.
“So much better tonight,” Boston coach Marco Sturm said. “We've seen it all year from our guys. We just had to wait a little bit unfortunately at the wrong time, but today you could see it. One goal against on the (penalty kill), that's it. That's more us. That made us good this year, that made us to be part of the playoffs, and we just got to remember ourselves. That's the way we have to play.”
Rasmus Dahlin scored for the Sabres, who are the No. 1 seed from the Atlantic Division. Lyon made 27 saves.
Buffalo leads the best-of-7 series 3-2. Game 6 will be at TD Garden in Boston on Friday (7:30 p.m. ET; ESPN, TVAS2, SN360).
“I said it this morning, it's going to be a real hard hockey game,” Buffalo coach Lindy Ruff said. “It was a hard hockey game. We had two or three really good chances we that didn't quite hit on in the third period. Even in overtime, we're looking at making a pass for a guy on a breakaway and we hit a stick. They’re changing and it ends up going the other way, but that's part of the game.”
Dahlin gave Buffalo a 1-0 lead on a power play at 3:35 of the first period. Jason Zucker's initial pass attempt for Tage Thompson was blocked by Bruins defenseman Andrew Peeke, but the puck bounced right back to Zucker, allowing him to then feed Dahlin, who buried a one-timer off the near post from the right circle.