The Chicago Blackhawks' deep stable of young talent made them the choice to defeat the Flyers when their series began for the Stanley Cup.

But youth can be prone to impatience and disarray against a more seasoned club, and the Flyers appeared to tap into those vulnerabilities in the two games they won at the Wachovia Center that evened the series at two games apiece.

As this gripping, dramatic series shifts back to the United Center in Chicago for Game 5, it's apparent the Blackhawks are not as composed as the Flyers. That is reflected in the number of penalties the Blackhawks have taken; the Flyers have done an admirable job of staying out of the penalty box.

The Flyers had 16 power plays in the first four games and scored five goals, one-third of their series total of 15. By contrast, the Blackhawks are 1 for 9, their only power-play goal coming with a two-man advantage late in Friday's 5-3 defeat. It's the largest statistical difference in the series so far.

"We have to be smart and more composed in the discipline area," Blackhawks coach Joel Quenneville said late Friday night after his team's furious attempt to overcome a 4-1 deficit fell short.

When Peter Laviolette was named Flyers coach after John Stevens was fired in December, one of his priorities was to instill discipline in a team that had strayed too far from the rule book. Until he took control, the Flyers were among the more self-destructive clubs in the NHL, forming a constant procession to the penalty box. Playing shorthanded not only increases an opponent's ability to score, but also it can be physically draining and a momentum killer.

Laviolette changed that, and the discipline he's demanded will be a major factor if the Flyers end up hoisting the Cup for the first time since 1975.

"Not to retaliate, we certainly talk about it as a group," Laviolette said. "Where we're at in the season and how far along we are in the playoffs, discipline I think plays a really big factor in hockey games."

The Blackhawks' lack of discipline put them at an early disadvantage in Game 4. Andrew Ladd was whistled for interference just 36 seconds after the opening face-off. The Blackhawks successfully killed off the penalty, but Tomas Kopecky caught Danny Briere with a high stick less than four minutes later. Kopecky barely had time to take a seat in the penalty box when Mike Richards scored on a spin-around backhander to give the Flyers the game's first goal.

"Our power play, I think, has been something we've leaned on throughout the playoffs," Richards said.

Along with avoiding penalties, the Blackhawks must get production from captain Jonathan Toews and winger Dustin Byfuglien, and better play from defenseman Niklas Hjalmarsson if they are to reverse the momentum the Flyers have built.

Toews' counterpart, Richards, was the best player on the ice Friday. Toews, the top all-around forward for Team Canada's gold medal team at the Vancouver Olympics, must match Richards' will and intensity. The 257-pound Byfuglien, who had eight goals through the first three rounds, has seemed more preoccupied with trading stick jabs with Chris Pronger than doing his job. Toews and Byfuglien have yet to score in the series.

Meantime, Hjalmarsson should have been awarded assists on the Flyers' first two goals because of egregious turnovers near Chicago's net.

"We have to start playing a lot smarter from the beginning," said Marian Hossa, a veteran whose words should be heeded by his teammates.