Giroux scored 26 seconds into the game for the only goal of the first period but the Flyers added three goals in each the second and third periods. Giroux assisted on the first and third goals of the second period.
The Flyers scored all seven goals against Islanders goaltender Evgeni Nabokov on 25 shots.
Jakub Voracek chipped in four assists, including helping on both of Giroux's goals. He and Giroux assisted on a goal by Matt Read and Read joined Voracek in assisting on both of the goals by Giroux.
Danny Briere scored the final two Philadelphia goals and Brayden Schenn and Zac Rinaldo also had goals as 11 Flyers players recorded at least one point.
Ilya Bryzgalov faced just 19 shots in posting his first shutout of the season. Monday marked his 400th NHL game and 30th career shutout.