Brock Nelson had a chance to give the Islanders the lead at 6:39 of the second, but Ersson stuck the left pad out to stop Nelson’s rebound chance.
Ersson stopped Julien Gauthier’s shot at 11:23, whipping out the right pad on a wrist shot.
Travis Konecny had a short-handed breakaway 38 seconds into the third period after a Mathew Barzal turnover, but Sorokin got a blocker on the shot.
Joel Farabee failed to tap home a pass to the glove-side post for the Flyers at 7:54 of the third period after a feed from Ryan Poehling.
Philadelphia outshot New York 36-22 in regulation and 4-3 in overtime.
“I thought it was just one of those games where you’ve just got to bear down and try and keep it simple,” Islanders defenseman Noah Dobson said. “Keep the shift short, and we battled, competed, and fought for a hard-fought point.”
NOTES: Flyers defenseman Rasmus Ristolainen was activated off long-term injured reserve and played in his first game of the season. He had three shots on goal in 17:49 of ice time. … Islanders defenseman Grant Hutton played 10:11 in his first NHL game since April 15, 2022, after being recalled from Bridgeport of the AHL on Saturday. … Sorokin became the eighth goalie to debut since 1929-30 with 18 shutouts prior to his 150th game.