Joffrey Lupul celebrates his overtime winner in Game 7 for Philadelphia. ((Nick Wass/Associated Press))

Joffrey Lupul's first goal of the NHL playoffs lifted the Philadelphia Flyers to a 3-2 overtime victory over the Washington Capitals in Game 7 of their series on Tuesday night.

Lupul put home a rebound from Kimmo Timonen's point shot on the power play at 6:06 of overtime, silencing the crowd at Verizon Center in Washington.

"I went to the net, the point shot came, I got a stick on it and the rebound came right back to me and I was able to just put it in," said Lupul. "It doesn't even sink in right away, everyone was on top of me so quick and it was just an unbelievable feeling."

Philadelphia will now take on the Montreal Canadiens in an Eastern Conference semifinal (Thursday, CBC, 7 p.m. ET). The Pittsburgh Penguins and New York Rangers battle in another series.

Scottie Upshall also scored for the first time in the playoffs for Philadelphia, with Sami Kapanen the other goal scorer.

Martin Biron came up huge for the Flyers, especially in the third period, finishing with 39 saves. Philadelphia was outshot 16-5 in the third.

Nicklas Backstrom scored for the fourth consecutive game for Washington, with NHL leading goal scorer Alexander Ovechkin tying the game 2-2 late in the second.

Cristobal Huet finished with 31 saves for Washington, which was trying to come back from a 3-1 deficit to win the seven-game series.

"They played their hearts out," said Boudreau. "They laid it on the line like you knew they would and that's probably why they're so sad.

"They're a proud group in there, and I think in the two overtime games, we were the better team, but we knew they were going to be resilient and I thought Marty had his best game of the series."

The teams exchanged power-play goals in the first. Ovechkin's bullet slapshot from the point bounced off the back boards and to the rookie Swede Backstrom, who potted his fourth of the playoffs at the 5:42 mark.

Washington ran into penalty trouble late in the period. Upshall scored on a slapshot with the man advantage at 15:38, although the Capitals were able to kill off a four-minute penalty later in the period.

Huet made big saves on Daniel Briere and Vinny Prospal to keep the score 1-1.

Philadelphia's go-ahead goal midway through the second was somewhat contentious. Patrick Thoresen of the Flyers bumped into Washington defenceman Shaone Morrisonn, which sent Huet sprawling out of the crease.

Veteran Kapanen had an empty net in which to deposit his second of the series.

Ovechkin goal comes during Downie penalty

Philadelphia coach John Stevens decided to play fiery rookie Steve Downie for the first time in the playoffs, and it backfired.

Ovechkin raced down the left face-off circle and snapped a shot between Biron's pads, just seconds after Downie's second penalty of the period lapsed.

Biron was outstanding in the third, foiling several Capitals, including sniper Alexander Semin.

"In the third it was almost like we got on our heels a little bit and they get the last matchup, so you want to use your fourth line a little bit but now here out comes [Ovechkin] again and you gotta be careful with him, he's such a dangerous guy," said Stevens.

In overtime, Washington's Tom Poti was cited for tripping, not long after teammate John Erskine was fortunate to avoid a penalty call. 

Philadelphia defenceman Timonen then got his second assist of the game, taking the shot that Lupul successfully converted into the winner.

"Timo was unbelievable," said Stevens. "He looked like he could play all night out there."

Daniel Briere also assisted, for his league-leading 11th point of the playoffs.

After sputtering on the power play early in the series, the Flyers scored twice with the man advantage in each of the last two games.

It was the first time all year Biron had won when playing the second of back-to-back nights. He had been 0-5.