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CHICAGO (AP) — When they won the first two games of the Stanley Cup finals, the Chicago Blackhawks were soaring. A trip to Philadelphia brought them back to reality in a hurry.

After two wins by the gritty Flyers on their home ice tied the series, the championship round is now a best-of-3.

Before Sunday night's Game 5 back at the United Center, the Blackhawks know they have adjust — to the Flyers' speed, to Philly's rugged defense led by veteran Chris Pronger, to their own inability to get scoring from their top players — or risk losing what they've come this far to achieve.

Coach Joel Quenneville is expected to mix some lines, and Chicago's defense hopes to give goalie Antti Niemi more support against a balanced Flyers' attack that has shown to be the Blackhawks' equal.

To re-establish themselves, the Blackhawks know they can't repeat their mistakes from Games 3-4. Defenseman Niklas Hjalmarsson's poor puck handling near the net led to a pair of first-period goals by the Flyers en route to a 5-3 victory.

And Chicago was too slow with a line change in Game 3, helping set up Philly's game-winning goal in overtime that produced a 4-3 victory.

Niemi, whose stellar play in the final period of Game 2 preserved a Chicago victory, gave up eight goals in the two games at the Wachovia Center.

"He's played well for us all season. ... We're not worried at all," Chicago's Brent Sopel said Saturday. "We left him high and dry as defensemen."

Philadelphia's Michael Leighton, meanwhile, ran his record to 8-2 with the victory Friday night. The former Blackhawk has a .924 save percentage and a 2.14 goals-against average. And his defense gave him great support in Game 4 with 28 blocked shots.

One of the Flyers' big advantages in the series has been on special teams. Chicago's power play is just 1-for-9 after converting a 5-on-3 Friday night, while Philadelphia is 5-for-16.

"We know we have to do a better job of staying out of the box," Sopel said. "We got to start taking pucks and bodies to the net."

That's where 257-pound Dustin Byfuglien is supposed to be the force for the Blackhawks. But Chicago's top line of Byfuglien, Jonathan Toews and Patrick Kane have combined for only one goal and four assists in the four games.

Byfuglien, bothered by the constant checking and stick work of Pronger, has not scored a goal and neither has Toews, the NHL's postseason points leader.

Quenneville did some switching late in Game 4. Kane was on a line with Dave Bolland and Kris Versteeg while Byfuglien and Toews were joined by Andrew Ladd.

Kane acknowledged how difficult it is to play against the 6-foot-6, 220-pound Pronger, long one of the NHL's nastiest and most talented defenseman. But he also pointed to the tough defense from Philly's forward for bottling up what had been a prolific first line in the postseason before the finals.

"He's really good with the puck. He's not just strictly defense, so that makes it tough on you when you're out there against him," Kane said of Pronger.

"He's pretty big. He has a big reach. He takes up a lot of time and space, but I'm going to give a lot of credit to the forwards and the way they've been coached as far as how to backcheck and play us in the zone off the top. That seems like where we're struggling a little bit."

No matter how Quenneville tries to match up, he knows the Blackhawks must do a better job of playing against Pronger, whom he once coached in St. Louis.

"We will want to make him turn and make him play defense and make him play from the back end," Quenneville said. "He's what he is. We have to be more physical and we have to be harder on him and make it tougher."

Chicago hopes its home crowd can be a major factor Sunday night but that kind of emotion can only carry a team so far. It's the matchups on the ice that matter the most. Game 6 is Wednesday in Philadelphia.

"You don't want something like this opportunity to slip away, especially coming all this way," Kane said. "It's been a long year. ... We can really put something together here that a lot of us can cherish for the rest of our lives."

But the Flyers are their toughest test of the postseason.

And Philadelphia is used to working its way out of holes and ending up on top. The Flyers erased a 3-0 deficit against the Bruins in the Eastern Conference semifinals before staging one of the great comebacks in NHL history to win the series.

"All we've done is just held serve throughout the first two games in Philly and it's 2-2," Flyers captain Mike Richards said Saturday. "We can't get too cocky or look too far ahead of what we've got to do tomorrow night."

But the Flyers certainly are confident based on how close they came to winning in the first two games in Chicago, losing by one goal each time.

To win the series, the Flyers must find a way to break through at the United Center. And now the momentum seems to be in their favor.

"There's a lot of pressure. I mean when you lose a game or you lose a couple of games you go home and you are wondering if you'll win the next game," Flyers coach Peter Laviolette said. "Usually desperation kicks in at that point. So I would expect that Chicago is going to come with a pretty good game tomorrow night. We know what we've got to win here."