It marked the first time since 2005-06 that the Flyers had won two in a row in Pittsburgh. Back then, the Pens played at the place they called the Igloo, an arena that was primarily a house of horrors for the Flyers.
Igloo II is more to their liking.
Giroux, who is emerging as one of the league's elite players, scored his fifth and sixth goals to tie Danny Briere for the team lead - and steer the Flyers (5-4-1) into first place in the Atlantic Division.
"Every game, he seems to get more confidence," coach Peter Laviolette said. "He's started to really bust out, it seems. Last year in the playoffs, I think, is where you started to see him [produce] in big games."
Fourth-line winger Dan Carcillo added his first goal - deflecting a Matt Carle drive under Marc-Andre Fleury's pads to give his team a 2-1 second-period lead - as the Flyers won their second in a row for the first time this season.
There were two fights, one major scrum, and nine penalties in the first 2 minutes, 35 seconds.
"The first period was weird . . . I think it's the first time in this league I've played three-on-three, so it was interesting," Giroux said. "But any time you battle like that and get a win on the road, it's huge."
Giroux said the Flyers had no early offensive flow because of the penalties.
"It's hard to get any rhythm, and you're not playing with your lines, either. You're always playing on the PK or PP," Giroux said. "But the second and third period, we started playing our game: Play deep, work hard, and win battles."
Giroux made the score 3-1 when he lifted a close shot into the net with 9:17 remaining. Ville Leino had kept the puck alive during a scramble in front, and the puck slid over to Giroux to the left of the net.
Pittsburgh (5-5-1), which made the score 3-2 on Tyler Kennedy's goal with 44.6 seconds left, is 2-4 in its new building.
The Flyers' penalty-killers were superb; they scored a goal, and the Pens were 0 for 6 on the power play.
If there were any questions about how the Flyers and Penguins feel about each other, they were answered right after the opening face-off.
It took all of six seconds for Mike Richards to square off with Pittsburgh's Matt Cooke - Richards rallied at the end to earn an entertaining draw against a player he tried to fight in Philadelphia on Oct. 16.
"It boiled over from the last game and some of the stuff that was said in the media," Richards said.
Seventeen seconds after Richards' bout, Jody Shelley's face was bloodied - he required some stitches - by the Penguins' Deryk Engelland.
With 11:48 left in the first period, Pittsburgh struck first when defenseman Kris Letang tapped in a perfect diagonal pass from Evgeni Malkin.
The Flyers, outshot, 10-4, in the first period, tied the game on Giroux's highlight-film maneuver with 14:40 remaining in the second period.
With the Flyers shorthanded, Richards raced into the Pittsburgh zone, but Letang ended his potential breakaway by diving and swiping the puck toward the sideboards. Richards then made a deft pass to the streaking Giroux, who went forehand-backhand and deposited his NHL-best third shorthanded goal (second against Pittsburgh) this season.
The Flyers controlled most of the second period and produced the go-ahead goal on a deflection by Carcillo with 6:26 remaining. The fourth line of Carcillo, Blair Betts, and Shelley kept the puck at Pittsburgh's end for a long time before the goal.
Carcillo, who had been benched in three of the previous five games, was playing because Laviolette expected a physical game. Nik Zherdev, demoted to the fourth line in Thursday's practice, was a healthy scratch.
Contact staff writer Sam Carchidi at 215-854-5181 or firstname.lastname@example.org. Follow on Twitter at www.twitter.com/BroadStBull.