Lightning goalie Johan Holmqvist, who stopped 29 shots in regulation, didn't allow a goal during the shootout. He earlier made a glove save on an in-close shot by Viktor Kozlov with 42.8 seconds left in the third.
Andy Hilbert hit the post on the Islanders' last shootout attempt. Rick DiPietro made 36 saves, including one on Vincent Lecavalier during a 2-on-1 with 1:29 left in overtime.
Nikita Alexeev and Brad Richards scored for Tampa Bay. Lecavalier, who had an 11-game point streak end Wednesday, had two assists.
The Islanders got goals from Radek Martinek and Mike York.