PHILADELPHIA (AP) - The Pittsburgh Penguins' road to the Stanley Cup finals along the Pennsylvania Turnpike took an unexpected detour.

The smooth ride through 12 playoff games got a bit bumpier when the Philadelphia Flyers staved off elimination from the Eastern Conference finals with a 4-2 victory Thursday night, forcing a Game 5 in Pittsburgh on Sunday.

Just as they did after taking a 3-0 lead over the New York Rangers in the second round, the Penguins were beaten on the road in Game 4. Pittsburgh wrapped up that series at home in its next chance, shaking off its only other loss in the playoffs (11-2).

The Flyers followed the lead set Wednesday by the Dallas Stars, who stayed alive in the Western Conference finals by avoiding a sweep at the hands of the Detroit Red Wings.

This is all new for Philadelphia, which had been swept the five other times it trailed 3-0.

The Penguins are 7-0 in the playoffs at home and have won 15 straight. They defeated the Flyers 4-2 there in the first two games of the series.

Only two NHL teams have recovered from an 0-3 deficit to win, the 1942 Toronto Maple Leafs and the 1975 New York Islanders, who rallied to beat the Penguins. Pittsburgh has led all three series this year 3-0, including a first-round sweep of Ottawa.

Joffrey Lupul got things going for the Flyers 8:27 in, and Danny Briere and Jeff Carter scored Philadelphia's second and third power-play goals of the series 7:02 apart to make it 3-0 in the first period.

Martin Biron showed the form that backstopped series wins over Washington and top-seeded Montreal in making 36 saves. Marc-Andre Fleury stopped 30 shots for the Penguins.

Jordan Staal, who returned to the Penguins following a one-day absence after the death of his grandfather, spoiled Biron's shutout bid with 16:44 left. He scored again with 5:49 remaining to transform Wachovia Center from joyous to nervous.

Lupul calmed the fears with an empty-net goal with 32.3 seconds left.

After trailing 11-4 on the shot clock midway through the first, the Flyers broke out against the previously sharp Fleury and finished the frame with a 17-13 edge.

In Tuesday's 4-1 loss in Game 3, Philadelphia managed only eight shots through two periods. The Flyers had 26 in the first 40 minutes this time.

Once they got the ever-elusive lead, the Flyers looked a little like the Penguins as they tried to clog up the neutral zone.

Pittsburgh has been doing that to perfection, allowing only 22 goals before Thursday. Fleury entered the game with a 1.74 goals-against average, but it took a beating early.

In a period the Flyers had been waiting four games to unleash, Philadelphia scored three times to take control for the first time in the series. After netting five goals in falling into an 0-3 hole, the Flyers struck for three in a span of 10:23.

Not bad for a club that hadn't been in front since the first period of Game 1, a lead that lasted only 1:21.

After going 1-for-9 on the power play in the first three games, the unit that was the NHL's second-best during the regular season started to click. It took time for the Flyers to overcome the loss of top defensemen Kimmo Timonen and Braydon Coburn, who are out with injuries.

Randy Jones fired a shot as he glided along the blue line, and the puck bounced off Fleury into the slot. Briere squeezed his way past 6-foot-7 defenseman Hal Gill and swept in a rebound from his knees at 11:48.

Carter also scored from in close, banging away at a rebound of R.J. Umberger's shot and finally knocking it past Fleury with 1:10 left in the period.

Philadelphia was successful in its first game with new lines. In an attempt to spark the offense, coach John Stevens moved Mike Richards up to play with Briere and dropped down slumping forward Vinny Prospal.

Notes:@ The Penguins were held without a power-play goal for just the third time in the playoffs. They are 1-2 in those games. ... Coburn wasn't healed enough from a swollen eye to return, but could be back for Game 5. ... Penguins LW Gary Roberts missed his second straight game with pneumonia. He is day to day. ... Pittsburgh lost 3-0 to the Rangers in its only other postseason defeat.