The Lightning missed their first chance to secure a spot in the Stanley Cup final.
Game 5 had been lucky for Tampa Bay and Tuesday's lined up to repeat the previous two series that went into overtime. The Islanders had the touch this time, however, pulling out a double-overtime 2-1 win over the Lightning at Edmonton's Rogers Place.
Tampa Bay still leads the series 3-2 and will get another opportunity to advance at 8 p.m. Thursday.
Center Anthony Cirelli's shot sailed wide and then moments later, defenseman Kevin Shattenkirk whiffed, creating a turnover. Winger Jordan Eberle picked up the puck, raced down the ice and beat Vasilevskiy to keep the Islanders' season alive.
This low-scoring, low-shot game fits the Islanders' style more directly than the Lightning's. But even while being limited to about two-thirds of their regular-season average, Tampa Bay managed to substantially outshoot the Islanders.
The Tampa Bay Lightning go down 2-1 in double overtime against the New York Islanders as Islanders' Jordan Eberle scores the game winning goal forcing a game 6 in the NHL Conference Finals.
Goalie Andrei Vasilevskiy went 12 minutes without seeing a shot at one point across the second and third periods.
Until overtime, the goals scored came from defensemen. Ryan Pulock put the Islanders on the board with a rocket from the left point with 4:19 left in the first period.
Victor Hedman, who is scoring at a career-high rate, matched him in the second period. He sank to about the top of the left circle to pounce on a rebound and place it top shelf.
Those stood as the only goals for more than 50 minutes into the second overtime.