Adam Hall and Sean Couturier also scored for the Flyers, who snapped a four-game losing streak. The Flyers (26-22-6) won an eighth straight game at home against the Red Wings (23-19-11), a franchise best against Detroit, which has not won in Philadelphia since the 1997 Stanley Cup final.
Mason recorded his second shutout of the season and the 21st of his career.
Starting in place of Jimmy Howard, who was back on the Detroit bench after missing three games with a knee injury, Jonas Gustavsson stopped 23 of 28 shots
The Red Wings were without three of their top forwards in Johan Franzen, Henrik Zetterberg, and Pavel Datsyuk. Franzen missed 16 games with a concussion and returned to action against the Florida Panthers on Sunday but is once again dealing with concussion symptoms. Zetterberg missed his third game with a bad back and Datsyuk his 11th with a lower-body injury. Detroit was also without Zetterberg and Datsyuk when it lost to the Flyers 6-3 at home on Dec. 4.
Hartnell opened the scoring with a power-play goal at the 6:18 mark of the first period when he redirected Kimmo Timonen's drive from the point and notched his second of the night 8:08 into the second period when he scored off a cross-ice pass from Giroux, who assisted on both of Hartnell's goals. Timonen later left the game with a lower-body injury and did not return.
Giroux tallied 10:22 into the the third, when his wrist shot from the left faceoff circle went off Gustavsson's glove and trickled into the net. Hartnell picked up the assist and each picked up their third point of the game.
Gustavsson made several acrobatic stops in the second - including one on another Giroux-to-Hartnell centering attempt - that kept the game from looking worse than it could have.
In the second period, Detroit's Luke Glendening, Kyle Quincy and Tomas Tatar all hit posts. Forward Riley Sheahan would have gotten the Red Wings on the board in the third, but his shot over the glove of Mason came after Flyers defenseman Nicklas Grossman dislodged the net, stopping play. Grossman was whistled for delay of game but Detroit, which came into Tuesday night with the league's top-ranked road power play, but failed to score on its four man-advantages.
NOTES: Hartnell was cleared to play Tuesday after being seen in a walking boot at the Flyers Wives Fight for Lives Carnival on Sunday. The forward has been dealing with soreness in his left foot for the last two weeks, but a CT scan came back negative. . Out of the lineup Tuesday night for the Flyers was winger Zac Rinaldo (ankle). Defenseman Andrej Meszaros was a healthy scratch. . For the Red Wings, Howard missed his fourth straight game but was on the bench backing up Gustavsson. Todd Bertuzzi was a healthy scratch.