The Penguins clinched their place in the second round of the Stanley Cup playoffs Wednesday, but still might not learn the identity of their next opponent until tomorrow night.

If Boston beats Montreal in Game 7 of their opening-round series at the Bell Centre tonight, the Penguins will face the Bruins in Round 2.

If the Canadiens win, the Penguins' uncertainty will continue unless Philadelphia is able to close out its series against Washington in Game 6 at the Wachovia Center this evening.

Should Montreal and Philadelphia both win tonight, the Canadiens and Flyers will meet in Round 2 and the Penguins will take on the New York Rangers.

But if Montreal and Washington win this evening, the Penguins' next opponent wouldn't be known until after the Capitals and Flyers meet in Game 7 at the Verizon Center tomorrow night.

Under that scenario, the Penguins would face Washington in Round 2 if the Capitals take Game 7 or New York if Philadelphia wins it.

Some of the Penguins are understandably eager to discover just who they'll be facing when the second round gets going later this week.

"We want to know who we're up against," center Jordan Staal said. "But it's out of our hands, so there's no point worrying about it."

Assistant coach Mike Yeo noted the positive aspects of having other Eastern Conference teams go through series that drag on.

"You have mixed emotions," he said. "Certainly, we'd benefit [if the opponent's identity were known] from the standpoint of having more time to prepare and you could concentrate more on who you're going to face, so it would certainly make your job easier.

"At the same time, I think that if those [series both] go to a Game 7 and we end up playing one of those teams, it's going to benefit us in the long run. So I don't mind putting in a few extra hours after the Game 7s are decided."

Left winger Gary Roberts, who has a sore groin, did not participate in practice for the second day in a row, but the Penguins aren't resigned to starting the second round without him.

Yeo said yesterday that Roberts likely would have been in uniform last week had there been a Game 7 in the Penguins' opening-round meeting with Ottawa -- the series ended in four -- and that the extended break should work to his advantage.

"We're fortunate to have the luxury of a little time off, so we don't want to push it," he said.

"We want to make sure that when he comes back, he's 100 percent and he stays in the lineup."

The Penguins have an obvious professional interest in Game 7 between Boston and Montreal tonight, since they will face the Bruins in Round 2 if Boston wins.

Regardless of how Game 7 plays out, however, they have been struck by Boston's resilience in overcoming a 3-1 deficit against a No. 1 seed that beat it eight times in a row in the regular season and three more in four tries at the start of Round 1.

"That's a team that obviously has no quit in it," Yeo said. "It's found a way to get it to Game 7, so you have to be impressed."

Defenseman Brooks Orpik certainly was by the way Boston bounced back after allowing a second-period short-handed goal in Game 6 to fall behind, 2-1, before rallying for a 5-4 victory.

"That could have crushed them, emotionally," he said. "The way they responded to that was pretty amazing. And they kept coming back in the third period."

Montreal will have the home-ice advantage tonight, although Penguins winger Pascal Dupuis noted that the crowd could work in Boston's favor if the Canadiens stumble.

"The fans are going to be behind them, but as soon as they get behind one or two goals -- if it does happen -- 'Oh, my God, all hell is going to break loose,'" he said.

This is, by the way, the seventh time a playoff series between the Canadiens and Bruins has gone to seven games, a figure unmatched in a major professional sport.

The Canadiens have won four of the previous six.

Penguins coach Michel Therrien, who sat out Saturday's workout because of illness, presided over yesterday's hour-long workout at Mellon Arena. ... The Montreal-Boston series is the 121st to go to a Game 7 since the NHL adopted a best-of-seven format in 1939. Home teams are 76-44.