Marian Gaborik scored at 14:41 of the third overtime on Wednesday night to give the New York Rangers a 2-1 series lead in their Eastern Conference semifinal series with Washington.
Gaborik was stationed in the slot to take a pass from Brad Richards behind the Washington net. The shot went off Washington goalie Braden Holtby's goal stick and into the net.
Gaborik, who hadn't score since the first game of the playoffs, converted after hitting the post a few minutes earlier.
The goals in regulation were scored less than five minutes apart midway through the second period.
Rangers captain Ryan Callahan scored on the power play from the slot past Capitals goalie Braden Holtby, with John Carlson replaying for Washington by picking off a New York pass attempt and beating goalie Henrik Lundqvist high.
Washington forward Troy Brouwer was denied early in overtime by Lundqvist after a puck squirted free in the slot. Alex Ovechkin hit the right post with five minutes left in the first extra session.
The Rangers swarmed near the end of the first overtime, with Michael Del Zotto's shot the beginning of a sustained volley that couldn't get through Holtby.
New York took a pounding in overtime. Lundqvist's goal stick clipped teammate Dan Girardi in the face, Ryan McDonagh was left dazed by a Matt Hendricks hit, and Brian Boyle was bloodied by an Alex Semin shot.
Boyle seemingly prevented teammate Michael Rupp's shot from going in during the second overtime, while in the third overtime John Mitchell of the Rangers blocked a strong chance and Lundqvist followed up with an impressive glove save on Dennis Wideman.
It was the longest NHL playoff game since Henrik Sedin lifted Vancouver over Dallas near the end of a fourth overtime in 2007.
New York won in overtime for the first time in three tries this spring. The Capitals are now 2-3 in overtime games.