Peter Diana, Post-Gazette photos Sidney Crosby takes a high stick from the Senators' Anton Volchenkov in the third period Sunday at Mellon Arena. Click photo for larger image. More Coverage: Penguins Notebook: Ottawa's Murray admires Armstrong's play Emery hasn't been team's soft spot Senators Notebook: Eaves 'OK,' still out for Game 4 FSN Pittsburgh criticized for lack of HD coverage Stanley Cup Playoffs Round 1: Game 4: 7 p.m. today TV: FSN Pittsburgh

Brooks Orpik wasn't a math major at Boston College -- he answered the most lofty of callings, communications -- but understands a little something about numbers.

Like how, even though the Penguins' first-round playoff series won't be over if they lose Game 4 to Ottawa tonight at Mellon Arena, their prospects for running off three victories in a row against the Senators would rival the odds of them winning the next Powerball jackpot.

"You look at it, you can't go down, 3-1," Orpik said yesterday. "Chances are that if you go down 3-1 against a team that good, you're not going to come back.

"You try to not look at the stats, the percentages of coming back. But I think everyone knows that against a team like that, you need a win [tonight]."

So technically, Game 4 doesn't qualify as a must-win for the Penguins. More like a must-win-if-you-want-to-be-realistic-about-it.

Perhaps nothing underscores the significance of this game like the Senators' record after Game 4 of previous series: They are 3-0 when they hold a 3-1 lead at that juncture, 1-4 when they are tied, 2-2.

Much as Ottawa coach Bryan Murray and his players have tried to separate themselves from their franchise's rancid playoff legacy, having this become a best-of-three could put excruciating pressure on a club that hasn't always handled it well.

Then again, the Senators' ability to exorcise their historical demons has no chance of becoming an issue unless the Penguins ratchet up their performance level. Significantly and quickly.

Play the way they did for most of the first three games, and they can start booking supersavers home for early next week.

Senators Mike Fisher celebrates a goal scored by Mike Comrie against the Penguins' Marc-Andre Fleury in the second period Sunday. Click photo for larger image.

"We have better," center Sidney Crosby said. "And we have to bring better."

No surprise there. Ottawa is one of the NHL's deepest and most talented teams and would have challenged -- if not overtaken -- Buffalo for first place in the overall standings if it hadn't stumbled through the first six weeks of the season.

"You know you're in for a heck of a battle when you play these guys," Penguins left winger Gary Roberts said. "I'm not surprised by how well they've played."

Much as they respect the Senators, though -- and could be forgiven if they were in near awe of Ottawa captain Daniel Alfredsson's work during the first three games -- the Penguins figure they've played a prominent role in how good Ottawa has looked so far.

"It's not really a matter of what they're doing," Orpik said. "It's a matter of what we're not doing."

The Penguins reviewed tape of their 4-2 loss in Game 3 during a team meeting yesterday, and Orpik came away feeling that "we pretty much dictated play the whole first and third periods."

The second period? Well, if the coaching staff is as details-oriented as it is reputed to be, every player probably had an air-sickness bag within easy reach.

"The second period just killed us again," Orpik said.

Roberts volunteered that "you're not going to play [only] 20 or 40 minutes real well and win" against an opponent with Ottawa's pedigree and personnel, and the outcomes of Games 1 and 3 reinforce that point.

Ottawa has been opportunistic throughout the series, adept at forcing mistakes and then exploiting them. The Penguins have been guilty of bad decisions and worse execution, and a lot of their errors get posted on the scoreboard immediately.

"In the playoffs, especially against a team like Ottawa that has a lot of dangerous players, if you give those guys opportunities, they're going to take advantage of them," Crosby said. "Unfortunately for us, we've made some big mistakes, and they've cost us."

Coach Michel Therrien attributed some of the Penguins' most grievous problems to lapses in focus -- "I don't think it's a matter of work ethic, I don't think it's a matter of will" -- and Orpik agreed.

"Everyone's working hard," he said. "Maybe not working smart."

That happens over the course of a season, sometimes at inopportune times. But something else happened during the 2006-07 season -- a 47-24-11 record -- that convinced the Penguins it's still a bit early to begin fine-tuning their concession speech.

"We didn't get 105 points for no reason," Orpik said. "I don't think it's any time to panic. But it's definitely a desperate situation."

Penguins Gary Roberts argues with a referee in the third period Sunday at the Mellon Arena.