Pittsburgh won all eight games against an once-dominating opponent that has won an average of nearly two of every three games played in the last 40 years between the Pennsylvania rivals. The Penguins went unbeaten against Philadelphia once previously, going 5-0-2 in 1992-93, but had never previously swept every game in a season.
They nearly didn't this time, falling behind 2-0 in a sloppily played first period in which Mike York and Braydon Coburn scored. But Gary Roberts scored once and set up the Penguins' other two goals in regulation as Pittsburgh won for only the second time in five games after getting points in 16 consecutive games (14-0-2).
Crosby decided a shootout for the second time in four days, following up Christensen's successful shot against goalie Martin Biron by stickhandling the puck down the slot before going to his backhand to end it.
Both Flyers shooters, Martin Ruzicka and Scottie Upshall, failed against goalie Marc-Andre Fleury after Christensen beat Biron by going to his forehand after faking a backhander. The Penguins are 7-5 in shootouts and the Flyers are 1-6, last winning on Oct. 26.
Crosby is only 3-of-11 on shootout attempts this season, but also decided the Penguins' 4-3 victory against the Rangers on Thursday by scoring the only goal of the shootout.
Crosby, the NHL's scoring leader with 98 points, was held without a point after getting 30 points in his first 15 career games against the Flyers. Crosby has two goals in his last 17 games overall, but has decided the last two Flyers-Penguins games - including a 5-4 decision on Feb. 8 - by scoring in shootouts.
Pittsburgh got back into the game the same way the Flyers took their 2-0 lead, by capitalizing on unnecessary penalties and controlling the puck in the opposing end for long stretches.
The Penguins cut it to 2-1 in the second period on Roberts' first goal in three games since being traded by Phoenix - off a Sergei Gonchar rebound three seconds after a power play created by Geoff Sanderson's slashing penalty ended. They tied it late in the period with only their second power-play goal in 20 chances over two games, this time with Roberts setting up Christensen on a give and go.
Fleury, benched recently for two games, tightened up after allowing the Flyers to go ahead 2-0 on a seemingly harmless Coburn shot from the blue line that somehow bounced between the goalie's pads from about 60 feet away.
The Flyers didn't score again until R.J. Umberger's tip-in from along the side of the net about seven minutes into the third, his 16th goal and fourth in three games. Christensen tied it with about 5 minutes remaining on a hard wrist shot from the low slot off Michel Ouellet's excellent pass from behind the net, his 12th goal.
Notes: The Penguins won despite going 1-of-8 on the power play. They are 2-for-24 in their last four games. ... The Flyers were outscored 38-17 in the season series. ... Pittsburgh played its third game within 72 hours following games Thursday and Friday nights. The Penguins are playing a league-high 17 games in March. .. Biron made his second start since being traded by Buffalo. He beat Pittsburgh 4-2 while with the Sabres on Nov. 17.