The Flyers (16-7-3) scored four times on 10 shots bridging the first and second periods after falling behind 3-0 to win their third straight.
Philadelphia also climbed out of a three-goal hole on Friday at Anaheim and won on another overtime goal by Giroux, who added three assists against the Sabres. Ilya Bryzgalov made 20 saves.
Zack Kassian had a goal and an assist, and Ville Leino, Thomas Vanek, and Drew Stafford also scored for the Sabres (14-11-2), who have lost three of four. Ryan Miller, playing in his second game after returning from a concussion and neck injury, stopped 29 shots.
The Flyers are an NHL-best 10-3-1 on the road. Buffalo has lost six of its last seven at home (1-4-2).
CAPITALS 5, SENATORS 3
OTTAWA (AP) — Alex Ovechkin scored one of three straight goals by Washington in the third period against Ottawa.
Nicklas Backstrom tied it at 2-2 with his 10th goal on a power play 9:45 into the third. He earned his 19th assist on Ovechkin's go-ahead goal at 13:50.