Wayne Simmonds and Max Talbot also scored during the big period, as the Flyers stretched their season-high winning streak to six games.
Ilya Bryzgalov earned the victory, turning aside 31-of-32 shots.
Capitals counterpart Tomas Vokoun was yanked after two periods. He let in four goals on 21 shots, with Michal Neuvirth stopping 11 shots in relief.
Jeff Halpern got Washington's goal.