PHILADELPHIA -- Early in the third period, a Flyers fan held up a sign directed at Washington that read, "You'll choke."

Not these Capitals, and certainly not against punchless Philadelphia.

Nicklas Backstrom scored, Braden Holtby had 26 saves, and the Washington Capitals beat the Philadelphia Flyers 1-0 on Sunday in Game 6 to win the series 4-2 and advance to the Eastern Conference semifinals.

The Capitals will play the Pittsburgh Penguins, setting up a marquee matchup of Alex Ovechkin vs. Sidney Crosby.

"It's going to be a hard series," Ovechkin said.

The Capitals scored two goals over the final three games of the series and clearly need more from Ovechkin and Co. to have a chance against the Penguins, who beat the Rangers in five games.

Against the Flyers, it was just enough, though.

Ovechkin had an assist on Backstrom's second-period goal that easily held against the Flyers.

Riding the momentum of Michal Neuvirth in net, the Flyers won two straight to force an unlikely trip home. Neuvirth was sensational again, but the Flyers were ultimately doomed by a power play that could not cash in against Holtby. The Flyers wasted nearly 2 minutes of a 5-on-3 power play in the second period that made a critical difference.

"We sacrificed our body 5-on-3," Ovechkin said. "We paid the price and we won."

The reward: keeping alive the pursuit of the first Stanley Cup championship in franchise history.

"It's a different group. The past is a different regime," Holtby said. "We are trying to write our own history."

Holtby, who had a 19-save shutout in Game 1, was barely tested with solid shots the last two games. The Flyers took only 11 shots against him in Game 5 and matched that feeble total midway through the second period. Most of their shots Sunday came from long range, and the Flyers never really attacked Holtby.

The Flyers entered a miserable 1 for 21 on the post-season power play.

Backstrom was whistled for a double minor for a high stick and Matt Niskanen was hit 5 seconds later for hooking, giving the Flyers 1:55 of a 5-on-3. The Flyers missed both shots with a two-man advantage. They later got hit with a penalty to make it 4 on 4 and wipe out the one-man edge.

"We just had to find a way to get a goal on the power play," Flyers captain Claude Giroux said.

The Flyers finished 0 for 3 on Sunday, but it's the 5-on-3 failure that will linger with them into the off-season.

The Capitals' penalty kill deserved credit, too.

"We watched a lot of their 5-on-3s and knew exactly what they were going to do," defenceman Karl Alzner said. "Holtby made some big saves and that was the turning point."

Backstrom helped Washington break Neuvirth's shutout streak that stretched 72 straight shots over nearly 110 minutes when he scored on a one-timer just below the circle with 8:59 left in the second period.

"Good pass, unbelievable shot," Neuvirth said. "I don't think I could have stopped it."

Neuvirth replaced the ineffective Steve Mason with the Flyers on the brink of getting swept headed into Game 4. He responded with two fantastic outings, highlighted by his 44-save effort in Game 5's shutout win. He stopped a flurry of shots, including a point-blank one-timer from Justin Williams -- late in the first period and skated off the ice to a thunderous standing ovation.

He was pulled after 28 saves with 1:30 left in the game for an extra skater. Not even a sixth Flyers skater helped.

Neuvirth, who went 18-8-4 with a 2.27 goal against and a .924 save percentage in 32 games, did his share to keep the Flyers in the series. But the Flyers' top line vanished in the series and gave them no real chance at pulling off an upset against the best team in the Eastern Conference. Giroux (67 points) had one assist in the series. Wayne Simmonds (60 points) had two assists. Brayden Schenn also failed to score a goal, leaving Philadelphia's top three goal scorers without one following a regular season where they combined for 80.

Giroux insisted he was not hurt, just "not good enough."

"We expected to win the series," he said."

Notes: The Flyers, who made a late-season surge under rookie coach Dave Hakstol just to reach the playoffs, have not won the Stanley Cup since 1975. ... Capitals D Brooks Orpik sat out with an undisclosed injury. ... Ovechkin and Crosby are playing each other in the post-season for the first time since 2009. ... Holtby earned his 20th career playoff win, tying Olie Kolzig for first on Washington's post-season list.