Nicolas Deslauriers, Noah Cates, Owen Tippett and Cam Atkinson also scored for the Flyers, who finished the preseason 3-2-1. Carter Hart made 14 saves.
Karson Kuhlman and Brian Pinho scored, and Semyon Varlamov made 26 saves for the Islanders.
Kuhlman gave New York a 1-0 lead at 9:53 of the first period.
Philadelphia responded with goals 1:09 apart later in the first from Deslauriers (15:15) and Cates (16:24) to take a 2-1 lead.
Tippett made it 3-1 when he scored on his own rebound for a short-handed goal at 8:14 of the second period.
Konecny one-timed a feed from Sean Couturier on a power play at 18:45 to make it 4-1.
Pinho cut it to 4-2 at 5:45 of the third period off a feed from Oliver Wahlstrom, but Atkinson responded at 7:39 for the 5-2 final.
