3 Things to Watch: Bruins at Sabres, Game 5 of Eastern Conference 1st Round

(1WC) Bruins at (1A) Sabres

Eastern Conference First Round, Game 5

Buffalo leads best-of-7 series 3-1

7:30 p.m. ET; HBO MAX, truTV, TNT, NESN, MSG-B, SNP, SNO, SNE, TVAS

BUFFALO -- This is it.

The Eastern Conference First Round Series between the Buffalo Sabres and the Boston Bruins has 
reached the do-or-die point. The Sabres, with a win on Tuesday, can move on to the second round.

The Bruins need a win or their season will end.

But this isn't any do-or-die Game 5.

The Bruins are coming off arguably their worst first period and worst performance of the season on Sunday in Game 4 at home, in a 6-1 loss, and are highly motivated to prove that it was an aberration for a team that has overachieved all year.

"I think we all feel and know how bad we were [on Sunday]," Bruins coach Marco Sturm said Monday. "I think the only goal now is how we're going to respond. That's the big one."

The Sabres, meanwhile, don't want to give an inch. Especially not at home. And they believe they are ready to respond, no matter what the Bruins throw at them.

"We've responded to all the challenges from the start of the year," coach Lindy Ruff said. "After Game 2 (4-2 loss), we responded. I think we know that they're going to bring their best. They're in a situation where again they've got to be desperate. They're going to be all-in on every situation. But I really felt after Game 2, we were kind of in the same situation. We needed to respond, we needed to play better, we did."

The Bruins have played their best hockey at KeyBank Center in this series, a reversal of a regular season in which they were vastly better at home.

They'll need that, right from the drop of the puck on Tuesday. It would help to get out to an early lead, something they've done in three of four games in the series, scoring first in Games 1, 2 and 3.

"Obviously we're not happy with what happened," Bruins forward Casey Mittelstadt said. "But at the same time, one game, and we've got to learn from it and flush it and move on. The next one's the biggest one. That's the thing about playoffs is sometimes you get beat down, but you can always come back, and we've got a big game coming up here."

Here are three things to watch in Game 5:

1. Bruins' defensive-zone play

The Bruins were a mess in their defensive zone in Game 4, unable to hold on to pucks, unable to clear the zone, unable to do much of anything. It was their own mistakes that cost them any chance of competing with the Sabres, something that was uncharacteristic of the Bruins this season.

"The mistakes were made were on us and gave them looks and gave them chances," Mittelstadt said.

They will need to clean that up to have any chance of extending their season.

As David Pastrnak said after Game 4 of what they have to do to change what happened, "It starts with defense and details. Have to play a tight-checking game, win a 1-0 game if we have to. Starting with the D-zone, better in front of our goalie."

Defense, after all, was supposed to be the hallmark of this team, a team without the top-level scoring threats boasted by other teams in the playoffs. So that defense, especially in getting the puck out of the zone to neutralize threats, will be paramount.

2. Closing it out

There have been few places more raucous in these Stanley Cup Playoffs than KeyBank Center last week for Game 1, and you can bet that the Sabres faithful will bring the same level of intensity with the team having a chance to close out the Bruins and advance to the second round for the first time since 2007.

So it'll be incumbent on the Sabres to not give an inch.

They're set up perfectly, coming off their most complete game of the postseason, heading back home to Buffalo, with all the momentum behind them. And while most of the Sabres haven't exactly been in this position before, they are fully aware of what's in front of them.

"They're going to come out flying," forward Zach Benson said. "And we know that. The fourth one's always the hardest to win. Clinching games in any sport are always the hardest and we know that. We're going to come prepared. We're going to try and get to our game as early as possible."

The Sabres have gotten healthy, with forwards Jason Zucker, Josh Norris and Tyson Kozak all available for Game 5, according to Ruff, though the morning lines suggested Zucker and Kozak will draw back in and Norris will not.

3. Lineup decisions for Boston

When the Bruins took the ice for practice on Monday, their lines were not all that different than in Game 4, with Michael Eyssimont in for Viktor Arvidsson and Mason Lohrei in for Nikita Zadorov, both of whom missed practice.

But Sturm cautioned not to put much stock in those lines or pairings.

"Don't look at the lines today, it's going to be different tomorrow," Sturm said Monday. "I need more with the decision about the lineups. There will be definitely some changes tomorrow. Today there were different areas that were more important than just lines."

Nor were his plans revealed on Tuesday morning, as they would normally be. With the Bruins opting to hold their usual morning skate, Sturm played his plans close to the vest, both in terms of whether Arvidsson and Zadorov would be available to play -- he called Monday's absences maintenance -- and who would be skating where.

Bruins projected lineup

Morgan Geekie -- Elias Lindholm -- David Pastrnak

Casey Mittelstadt -- Pavel Zacha -- Viktor Arvidsson

Lukas Reichel -- Fraser Minten -- Marat Khusnutdinov

Tanner Jeannot -- Sean Kuraly -- Mark Kastelic

Jonathan Aspirot -- Charlie McAvoy

Hampus Lindholm -- Jordan Harris

Nikita Zadorov -- Andrew Peeke

Jeremy Swayman

Joonas Korpisalo

Scratched: James Hagens, Alex Steeves, Henri Jokiharju, Michael Eyssimont, Mason Lohrei

Injured: None

Sabres projected lineup

Peyton Krebs -- Tage Thompson -- Alex Tuch

Jason Zucker -- Ryan McLeod -- Jack Quinn

Zach Benson -- Noah Ostlund -- Josh Doan

Jordan Greenway -- Tyson Kozak -- Beck Malenstyn

Rasmus Dahlin -- Mattias Samuelsson

Bowen Byram -- Owen Power 

Logan Stanley -- Connor Timmins

Alex Lyon

Ukko-Pekka Luukkonen

Scratched: Josh Dunne, Colten Ellis, Michael Kesselring, Tanner Pearson, Luke Schenn

Injured: Josh Norris (undisclosed), Sam Carrick (upper body), Jiri Kulich (blood clot), Justin Danforth (lower body)

Status report

The Bruins did not hold a morning skate. … Arvidsson and Zadorov each missed practice Monday because of maintenance; Arvidsson left during the first period of Game 4 on Sunday with an upper-body injury and did not return. Eyssimont, a forward, filled in for Arvidsson at practice and Lohrei, a defenseman, skated in Zadorov's spot. … Zucker and Kozak are expected to play after each left in the third period of Game 4 for undisclosed reasons. ... Norris rejoined the team and is available after missing two games with an undisclosed injury, Ruff said; the forward did not take any line rushes during the skate.