UNIONDALE, N.Y. -- Center John Tavares scored just 15 seconds into overtime Sunday afternoon as New York Islanders edged the Washington Capitals 2-1 in Game 3 of the Eastern Conference quarterfinals at a delirious Nassau Coliseum.

The Islanders lead the best-of-7 series 2-1. It is their first series lead after three games since 1993.

Tavares put back the rebound of a shot by left winger Nikolay Kulemin. It trickled past Capitals goalie Braden Holtby and over the red line as the sellout crowd erupted.

Game 4 is scheduled for Tuesday night in Uniondale.

Right winger Kyle Okposo scored for the Islanders while goalie Jaroslav Halak made 24 saves.

Center Nicklas Backstrom scored late in the third period for the Capitals. Holtby, who missed Game 2 with the stomach flu, recorded 40 saves.

The Islanders outshot the Capitals 16-5 during a feisty first period. A pushing-and-shoving match between the teams just 3:36 after faceoff resulted in Washington left winger Curtis Glencross being whistled for unsportsmanlike conduct.

Capitals center Eric Fehr and left winger Marcus Johansson both left with injuries in the first period, though Johansson returned for the final two periods.

There was also an eight-man pileup in front of the Islanders net after a series of point-blank putback attempts by the Capitals ended with Halak and Islanders center Anders Lee losing their helmets.

Okposo and defenseman Lubomir Visnovsky were both injured in the first half of the second period. But both players factored into the tie-breaking goal with 8:23 left, when Okposo got a stick on a slap shot by Visnovsky.

With the Coliseum crowd roaring, the Islanders continued to pepper Holtby over the next five minutes but could not extend the lead despite numerous redirections in front of Holtby.

The Capitals regained some momentum when Islanders defenseman Brian Strait drew a high-sticking penalty with 1:20 left. But New York ended the period on a high note when defenseman Johnny Boychuk, who had fallen to the ice to try and block an Ovechkin shot, managed to whirl around on his stomach and get his stick on the puck with three seconds left.

The Capitals dominated the third period and finally tied the game with 6:06 left, when Backstromn's shot sailed through a crowd of players in front of Halak, hit the top of the goalpost and bounced into the net.

Washington outshot the Islanders 12-7 in the third, though New York had several chances in the waning minutes. But Tavares could not redirect a shot by defenseman Nick Leddy from just inside the blue line and Holtby gloved slap shots by right winger Cal Clutterbuck and left winger Matt Martin.

NOTES: The Islanders had five healthy scratches -- LW Eric Boulton, D Matt Donovan, RW Michael Grabner, RW Colin McDonald and D Griffin Reinhart -- as well as D Travis Hamonic, who hasn't played since suffering an undisclosed injury against the Pittsburgh Penguins on April 10. ... The Islanders have not had home ice advantage in a playoff series since 1988. ... With G Braden Holtby healthy enough to start, the Capitals scratched third-string G Justin Peters as well as LW Andre Burakovsky and C Michael Latta. ... Capitals G Philipp Grubauer, who earned the win in relief of Holtby, could head back to Hershey for the AHL playoffs, which begin this week.