BUFFALO, N.Y. — The Buffalo Sabres knew the Boston Bruins were going to be desperate.

Before the Sabres had even packed their bags and left TD Garden after a 6-1 win in Game 4 that pushed their series lead to 3-1, they were already talking about how much different Game 5 would be.

“I think the challenge is the team that’s gonna come in there, they hit their highest desperation level,” Sabres coach Lindy Ruff said.

Bruins defenseman Nikita Zadorov set that same tone for his team when he spoke before the game.

“Everybody saw the result,” Zadorov said of Game 4. “It is a slap to the face and just cannot happen with our team, our organization, our identity. Today we’ve just got to come out and play like it’s the last game of our lives. Like our life is on the line. We’ve just got to go out there and try to die on the ice.”

That was the case when the Bruins returned to Buffalo for Game 5. After the Sabres took an early 1-0 lead on a power-play goal from Rasmus Dahlin, the Bruins started to play like their season was on the line. A second-period goal from Elias Lindholm tied the score at one and set the stage for a dramatic third period. Through two periods, the Bruins had an 8-2 advantage in high-danger chances at five-on-five, according to Natural Stat Trick.

After killing off an Alex Tuch high-sticking penalty early in the third period, the Sabres took control of the game. But despite five high-danger chances in the period, the Sabres couldn’t beat Jeremy Swayman again in regulation. They didn’t manage to seriously test him much, either.

That set the stage for overtime. After the Sabres were controlling play early in OT, David Pastrnak snuck behind Buffalo’s defense and beat Alex Lyon for the game-winning goal to extend the series.

Noah Östlund leaves game with injury

Noah Östlund left the game in the first period with an apparent left leg injury. He got tangled up with Bruins forward Casey Mittelstadt in the corner, and Mittelstadt fell on Östlund’s left leg. Östlund’s knee and ankle both twisted awkwardly. Östlund screamed in pain before making his way to the bench and going right down the tunnel. Later in the period, he tried to test out the injury during a TV timeout and went right back to the dressing room.

Östlund came back from an injury to make his series debut in Game 3 and was an immediate spark for the Sabres. He had a goal and an assist in his playoff debut. He had recently been bumped up to Buffalo’s top power-play unit and was helping that group generate more chances. If Östlund misses significant time, that’s a major loss for the Sabres. He’s been the team’s best playmaker since he entered the lineup. The 22-year-old helped change this series, and the Sabres don’t have an obvious replacement on the roster. Josh Norris has missed the last three games with an injury, but Ruff said he was available to play in Game 5. He’d be the most likely option to replace Östlund in the lineup. Tyson Kozak moved into Östlund’s spot at center between Zach Benson and Josh Doan for the remainder of Game 5.

Viktor Arvidsson sidelined

Viktor Arvidsson did not play in Game 5. The Bruins’ No. 2 right wing did not travel to Buffalo. He suffered an upper-body injury in the first period of Game 4.

With Arvidsson unavailable, coach Marco Sturm broke up his top three lines. Pavel Zacha, usually the No. 2 center, moved up with Marat Khusnutdinov to the first line with David Pastrnak.

Fraser Minten centered the second line with Mittelstadt and Morgan Geekie. Elias Lindholm, formerly the No. 1 center, was on the third line with Alex Steeves and Mikey Eyssimont. Steeves and Eyssimont were healthy scratches for the first four games.

On defense, Henri Jokiharju made his series debut. The ex-Sabre replaced Jordan Harris on the second pair.

Sabres finally get a power-play goal

The Sabres came into the game on a 0-for-39 slump on the power play. Doan had scored a goal a second after a power play expired in Game 4, but the Sabres were still searching for something on the man advantage. They got on the board early in Game 5 with Jason Zucker setting up Dahlin for a power-play goal in the first period. The Sabres’ power play also generated six scoring chances and four high-danger chances on two chances in the second period. After Östlund left with an injury, the Sabres used Ryan McLeod on the top unit and also mixed in a look with Owen Power operating as a second defenseman with that group. The fact that the Sabres built a 3-1 series lead without a single power-play goal speaks to how dangerous this team could be with a legit power play. The Sabres aren’t there yet. But they are showing some encouraging signs.

This story will be updated.