Nobody knows better than the Flyers how unlikely and how difficult the challenge facing the Pittsburgh Penguins is. Only four teams in the history of North American major-league sports ever came back from an 0-3 deficit to win a seven-game series, and the Flyers are the most recent.

"It hasn't been done very often," Scott Hartnell said after a brief practice Thursday. "You look at the stats. Three or four teams have done it in history. We were one of them, a few years ago."

Well, some of them. If James van Riemsdyk returns to the lineup, there will be just seven Flyers left from the team that staged the ultimate comeback against the Boston Bruins in 2010. They include leaders like Hartnell, Danny Briere, Claude Giroux and Kimmo Timonen - and, perhaps more important, the coaching staff is the same.

The roster turnover might have more impact if the Flyers were trying to replicate the feat. But they're not. They're merely trying to replicate the common feat of closing a team out after taking a 3-0 lead.

Can their experience from 2010 help? Hartnell didn't really think so.

"That was great to be a part of," Hartnell said, "but we can't think about a comeback or us collapsing. We have to focus on one game."

I covered every remarkable minute of that 2010 Eastern Conference semifinal, and two relevant factors stand out. The Flyers remained remarkably calm through a week's worth of elimination games. And the Flyers somehow convinced themselves and, evidently, the Bruins that the pressure was really on Boston to get that fourth win.

Minutes after the Flyers won Game 4 in Philadelphia, goalie Brian Boucher set the tone - even turning the Bruins' home-ice advantage around.

"The pressure's on them now," he said. "They're going home, and we still have nothing to lose."

That pressure, real or imaginary (and what's the difference, really?), mounted with each Flyers victory.

Before Game 7 in Boston, Briere summed it up.

"You look at Boston, blowing a 3-0 lead," he said. "Everybody feels it. They got booed out of their building last game. I expect them to come out with a lot of desperation, but there's also going to be extreme pressure on them to perform. They can't afford to make any mistakes because things can turn on them pretty quick. "

It was the hockey equivalent of a Jedi mind trick. What's interesting here is whether, having performed it themselves, the Flyers are immune to such trickery from the Penguins.

For now, the pressure is entirely on Pittsburgh. The Penguins staved off elimination with a wild 10-3 win Wednesday night at the Wells Fargo Center, but they will face it again Friday night in Pittsburgh.

The Flyers are still playing with house money in Game 5. They quieted two sellout crowds last week, spotting the Penguins multiple-goal leads and then storming back for stunning victories. There is nothing about the venue or the opponent that the Flyers haven't already handled.

"After four games, to be 3-1, a lot of guys would have taken that," Jaromir Jagr said. "That's the way we have to look at it."

"If you told us we were going to beat Pittsburgh in four games," Giroux said, "we'd have said, 'No way.' Now we're in a position, we're up 3-1. We're in great position. We didn't win the first three games with luck. We were doing some great stuff out there."

There's no doubt about that. The Flyers played with energy and confidence that the Penguins simply couldn't match in the first three games of this series. The reverse was true in Game 4. Whether that was a matter of feeling as if they had the series in the bag or whether there was a true switch in momentum, well, that's what Game 5 is all about.

If the Flyers win, they move on and Game 4 is written off as no more than a learning experience for their young players. If the Penguins win, then things start to get interesting.

The math and the history still say the Flyers are likely to win the series. They would be coming home for Game 6. They'd still need to win just one game while the Pens would need to win two.

The pressure, however, definitely shifts at that point. The Penguins start seeing how this comeback is a real possibility while doubt begins to seep into the Flyers' minds. And after Wednesday's debacle, the home-ice advantage means about as much to the Flyers as it does to the Penguins in this crazy series.

The Flyers became the first NHL team in 37 years to stage the ultimate comeback. The weight of history is certainly on their side now. The best way to keep it there is to finish this thing in five.

Contact Phil Sheridan at 215-854-2844, psheridan@phillynews.com, or on Twitter @Sheridanscribe. Read his blog, "Philabuster," at http://go.philly.com/philabuster. Read his columns at www.philly.com/philsheridan