PHILADELPHIA -- When you're down 3-0 in a playoff series and you win that first game to stave off elimination, it's like that dark cloud you see off on the horizon.
At this stage, the Flyers' life-saving 4-2 home victory Thursday night is but a speck on the horizon of this Eastern Conference finals series.
Is it the promise of a storm, of something more from a Philly squad that rose from the dead with perhaps its best game of the postseason? Or will it peter out and become nothing more than a light breeze blowing on the Penguins' backs as they head to the Stanley Cup finals for the first time since 1992?
"There's a saying that when the team that's behind in the series, it's like backing a cat up in the corner or something like that," Philadelphia defenseman Derian Hatcher said. "That's usually when they fight their hardest."
Here is the problem for the Flyers -- apart from needing to win three straight games against the best team in the playoffs, a team that boasts an 11-2 record even after Thursday's loss -- they face the prospect of having to do exactly the same thing, maybe more, Sunday and having to do it on the road.
Or maybe it's more a challenge than a problem.
"I think now we look at it as it's a series now, 3-1, anything can happen," Flyers forward Scottie Upshall said. "This next game is going to be huge. I think the first period of the next game is just what we've got to concentrate on now."
He's probably right.
Heading into Thursday's game, Philly had been outscored 6-3 in the first period over the first three games of the series. By the time the horn sounded to end the first in Game 4, the Flyers owned a 3-0 lead.
The opening goal came after a furious stretch of hockey that saw Mike Richards miss on his third short-handed breakaway of the series (he has scored on one of them), then saw the Pens' Marian Hossa break in at the other end of the ice and force Martin Biron into a sparkling right-pad save.
But, in the end, it was Joffrey Lupul who broke the ice, streaking down the right side after the Flyers had killed off the first penalty of the game and ripping a shot that deflected off defenseman Hal Gill's stick and over Marc-Andre Fleury's shoulder. It was the first time Philly had led in the series since the 12:50 mark of the first period of Game 1. That lead lasted just 1:21, but the Flyers would hold on in Game 4 despite a third-period charge by the talented Pens.
Daniel Briere followed the Lupul marker on a Flyers power play 3:21 later. It was just the second power-play goal in the series for Philly. The Flyers' third goal, by Jeff Carter, also came on the power play, this time with 2:50 left in the opening frame.
Richards thought that the Flyers' patience was one of the keys to the victory and that patience was especially important on the two power-play goals.
"I thought, before, we were trying to get it up top right away and get shots when they were doing a good job blocking the lanes," Richards said. "Just keep it until we have the shot. We said before we have two minutes to score a goal, we don't have to do it in the first 10 seconds."
The Penguins, on the other hand, were denied a power-play goal for only the third time in 12 games this spring. They were beaten to pucks. Their pinpoint passes that had created scoring chances in the first three games were intercepted or blocked or went astray. And when they did find the net, Biron was as good as he could be, turning away 36 of 38 shots. In the first three games, he had allowed 10 goals on 82 shots for an ordinary .878 save percentage.
Plus, for the first time this postseason, both Sidney Crosby and Evgeni Malkin were off. Crosby seemed to lose his cool a bit, engaging in a long jawing match with Richards as the two went to the bench in the third period. Later, the two centers exchanged hacks after the Flyers had scored an empty-net goal to make it 4-2.
What did Richards say to Crosby?
"Ah, nothing really. Same old stuff, I guess," Richards said with a grin.
But, surely, it doesn't hurt to get Crosby riled up.
"I think you want to take him out of his element a little bit, get him off his game, but, I mean, he's heard it all before," Richards said. "He's not going to get too rattled or anything like that. We can't lose our composure and run out of position to try and hit him, but if the opportunity's there, we're not going to back down."
One of the popular words uttered in the happy Flyers dressing room was "momentum."
But does momentum, as fickle a thing as there is in sports, come from one game?
The New York Rangers, the Penguins' second-round opponent, talked of being part of history when they were down 3-0. They won at home, just as the Flyers did, to keep their season alive for another day, then erased a 2-0 Penguins lead in Game 5 only to lose in overtime. All that talk of history was suddenly moot.
One of the reasons teams sometimes struggle to seize whatever momentum they've gained from winning that first game with their backs against the wall is the emotional price of that victory.
Staring at a long summer of what-ifs, the Flyers produced an inspired effort. The Penguins' emotional investment in Game 4 was a fraction of that. The Penguins talked about needing to match the Flyers' desperation. Easy to say but hard to do, especially when you're 11-1 in the postseason when the puck drops.
By the time the third period rolled around, it was Pittsburgh forcing the issue and Philadelphia looking more like the Philadelphia of Games 1, 2 and 3. Jordan Staal scored twice and the Penguins outshot the Flyers 13-8 in the third.
"Bottom line, we got the win," Philly coach John Stevens said. "I thought it was a gutsy effort by our team. I'd like to keep it 3-0 when we get it there, but we seem to have a way to make it exciting one way or another."
So, what do the Flyers have left?
If you believe them, this win is a tonic and this is now a series, but it might just as easily be a last, gutsy outpouring of will.
Soon, we will know for certain.
Scott Burnside is the NHL writer for ESPN.com.