PITTSBURGH -- The Washington Capitals could advance to the Eastern Conference Final for the first time since 1998 and eliminate the two-time defending Stanley Cup champion Pittsburgh Penguins with a win in Game 6 of the second round at PPG Paints Arena on Monday.

Capitals center Nicklas Backstrom will be a game-time decision. He left Game 5 on Saturday at 6:48 of the third period because of an upper-body injury and did not take part in the morning skate Monday.

[RELATED: Backstrom game-time decision in Game 6 | Complete Capitals vs. Penguins series coverage]

The Penguins are 4-0 when facing elimination from the playoffs under coach Mike Sullivan.

Here are 5 keys for Game 6:

1. Backstrom's health

Backstrom is tied for second on the Capitals during the playoffs with 13 points (three goals, 10 assists), one behind forward Alex Ovechkin. He has five points (one goal, four assists) in five games against the Penguins.

Lars Eller, who replaced Backstrom on the second line during Game 5, skated in Backstrom's spot between Jakub Vrana and T.J. Oshie.during the morning skate.

"I think our history shows that other guys can step up when need be," Eller said. "Regardless of if Nick is playing or not, we're confident we can get a win."

2. Murray recovering

Penguins goalie Matt Murray hasn't been as solid as he was when helping Pittsburgh win the Stanley Cup the previous two seasons. He is 6-5 with a 2.49 goals-against average and .905 save percentage in 11 games this year.

After making 20 saves in a 3-1 win in Game 4, Murray allowed four goals on 30 shots in a 6-3 loss in Game 5.

The Penguins need the Murray from the previous two postseasons in goal Monday.

Video: PIT@WSH, Gm5: Murray uses his stick to deny Ovechkin

3. Capitals adjusting top line

Vrana was shifted to the top line during Game 5, and with Washington losing 3-2 entering the third period he had the primary assist on Evgeny Kuznetsov's tying goal 52 seconds in and scored the game-winner at 15:22.

The Capitals had Chandler Stephenson at first-line right wing with Kuznetsov and Ovechkin during morning skate. He has one goal this series.

4. Experience

The Penguins are well-versed in dealing with adversity. They have not lost an elimination game since April 24, 2015, when the New York Rangers defeated them 2-1 in overtime in Game 5 of the Eastern Conference First Round.

Sullivan and Murray never have lost a playoff series with the Penguins, who are 9-1 all-time in series against the Capitals.

"It's all about an attitude going into it," Sullivan said. "It's the first team that wins four games, not three."

The Capitals are 0-3 in series against the Penguins during the Sidney Crosby/Ovechkin era. Washington lost in the second round in 2009, 2016 and 2017, with Pittsburgh going on to win the Stanley Cup.

"You want to win the game and move forward," Ovechkin said. "It's not going to be easy."

5. Letang returning to form

Penguins defenseman Kris Letang hasn't played up to expectations since having neck surgery April 13, 2017. That's continued to be the case in this series.

Letang has three points (one goal, two assists) in the first five games. That isn't concerning, but his untimely defensive miscues have been, including losing his coverage on Kuznetsov on the game-tying goal in Game 5.

The Penguins need him to avoid those mistakes in Game 6.

"Just going to focus on playing our game and doing what we do best," Letang said. "That's it."

Capitals projected lineup

Alex Ovechkin -- Evgeny Kuznetsov -- Chandler Stephenson

Jakub Vrana -- Lars Eller -- T.J. Oshie

Brett Connolly -- Travis Boyd -- Devante Smith-Pelly

Nathan Walker -- Jay Beagle -- Alex Chiasson

Dmitry Orlov -- Matt Niskanen

Michal Kempny -- John Carlson

Brooks Orpik -- Christian Djoos

Braden Holtby

Philipp Grubauer

Scratched: Jakub Jerabek, Madison Bowey, Pheonix Copley, Shane Gersich

Injured: Andre Burakovsky (upper body), Nicklas Backstrom (upper body)

Suspended: Tom Wilson

Penguins projected lineup

Jake Guentzel -- Sidney Crosby -- Dominik Simon

Carl Hagelin -- Evgeni Malkin -- Patric Hornqvist

Bryan Rust -- Riley Sheahan -- Phil Kessel

Tom Kuhnhackl -- Derick Brassard -- Conor Sheary

Brian Dumoulin -- Kris Letang

Olli Maatta -- Justin Schultz

Jamie Oleksiak -- Chad Ruhwedel

Matt Murray

Casey DeSmith

Scratched: Daniel Sprong, Carter Rowney, Matt Hunwick, Josh Jooris, Tristan Jarry, Michael Leighton, Garrett Wilson, Jarred Tinordi, Lukas Bengtsson, Jean-Sebastien Dea, Adam Johnson, Teddy Blueger, Thomas Di Pauli, Chris Summers, Andrey Pedan

Injured: Zach Aston-Reese (broken jaw/concussion)

Status report

Boyd and Walker could make their Stanley Cup Playoff debuts. Boyd would play if Backstrom is out. … The Penguins did not hold line rushes during a full morning skate.