UNIONDALE, N.Y. -- Center Nicklas Backstrom scored with 8:51 left in overtime Tuesday night to lift the Washington Capitals to a 2-1 victory over the New York Islanders in Game 4 of the Eastern Conference quarterfinals at Nassau Coliseum.

With the win, the Capitals tied the best-of-seven series at two games apiece. Game 5 is Thursday night in Washington, D.C.

Seconds before the game-winner, the Capitals won a faceoff in the Islanders' zone. Backstrom's shot went between the legs of right winger Joel Ward and past Islanders goalie Jaroslav Halak.

Left winger Alex Ovechkin scored in regulation for the Capitals while goalie Braden Holtby recorded 36 saves

Center Casey Cizikas scored in the first period to tie the game at one for the Islanders. Halak made 28 saves.

The Islanders were the more aggressive team early after starting hit-heavy fourth-line forwards Cizikas, Cal Clutterbuck and Matt Martin.

New York also had the first scoring threats after Ovechkin was whistled for tripping left winger Nikolay Kulemin just before the midway point of the period. But Holtby turned away a wraparound effort by center Anders Lee and stick-less Backstrom blocked a shot by defenseman Nick Leddy.

The Capitals went up with 6:54 left in the opening period. After winning a faceoff, the puck ended up with defenseman John Carlson, whose shot ticked off Ovechkin and past Halak.

The Islanders tied it with just 12.6 seconds remaining when a shot by Clutterbuck seemed to take a funny bounce as it skittered toward Holtby. Cizikas swooped and put back the rebound for New York.

The Islanders outshot the Capitals 15-6 in the second period but failed to score on three power plays.

In the third period, Halak made a pair of impressive saves on point-blank power-play shots by Ovechkin and left winger Marcus Johansson, with the latter's shot at an open being snagged by the goalie.

The Islanders had an even better chance seconds before a power play expired, when Clutterbuck raced up the right side of the ice and fired a shot that bounced off the crossbar and out.

NOTES: The Islanders had 12 scratches, including six players recalled Monday from Bridgeport of the AHL. Their only injured player is D Travis Hamonic, who hasn't played since suffering an undisclosed injury against the Pittsburgh Penguins on April 10. He did not participate in the morning skate Tuesday but was at the Coliseum. ... The Capitals scratched C Eric Fehr, who is expected to miss at least the next two games with an upper-body injury suffered Sunday, as well as LW Curtis Glencross and G Justin Peters.