The Senators ended a five-game home losing run and won a first shoot-out win of the season after losing four straight.
Clarke MacArthur had two regulation goals for the Senators, and Patrick Wiercioch and Kyle Turris also scored. Craig Anderson made 25 saves.
Michael Raffl, Jakub Voracek, Luke Schenn and Kimmo Timonen had goals for the Flyers, Steve Mason stopping 30 shots.
Evgeni Malkin scored in his return from a lower-body injury and Sidney Crosby added his 16th goal as the Pittsburgh Penguins beat the Columbus Blue Jackets 2-1.
Marc-Andre Fleury stopped 32 shots for the Penguins, who won their sixth straight home game.
Vancouver defeated Carolina 2-0 and Anaheim were 5-2 winners over the New York Islanders.