WASHINGTON - All eyes were on Braden Holtby in his first chance to tie Martin Brodeur's single-season wins record. Then, New York Islanders rookie Christopher Gibson stole the show at the other end.

Gibson made 29 saves in his first career NHL start as the Islanders rallied from two goals down in the third period and beat the Washington Capitals 4-3 in overtime Tuesday night to clinch a playoff berth amid a seemingly never-ending torrent of injuries.

Gibson, the Islanders' fourth-string goaltender pressed into duty in the second half of back-to-back games, bounced back from allowing a goal on the second shot he faced and stopped Evgeny Kuznetsov on a breakaway in overtime to pave the way for the victory.

"In my mind I was like, 'I have to stop this to keep this going,'" Gibson said. "Lucky enough I made the save there, and we won the game."

Coach Jack Capuano called Gibson the Islanders' best player on the ice, and he had to be against the league-leading Capitals. Alex Ovechkin scored his 46th and 47th goals of the season and T.J. Oshie added his 22nd, but Gibson was solid and didn't crack under pressure.

Neither did his teammates, who stared down a 3-1 deficit in the third. Kyle Okposo and Anders Lee scored 1:45 apart to tie it, and defenceman Thomas Hickey returned from a skate-cut scare to score the game-winner 2:13 into overtime.

The Islanders would have clinched a playoff spot minutes later when the Carolina Hurricanes defeated the Boston Bruins in a shootout, but Okposo said players wanted to do it on their terms. It took a furious comeback, and now New York is back in the playoffs for the third time in four years.

"We didn't wait for someone else to do it for us," said Hickey, who called the skate cut minor. "To come in here in the back end of a back-to-back and have some guys step up like Gibby and play through a little adversity there, that's the right way to do it. You'd rather do it the hard way than the easy way."

Injuries have made things difficult for the Islanders for several weeks now. They lost starting goalie Jaroslav Halak last month, and played their third game without top defenceman Travis Hamonic, and on Monday night defenceman Calvin de Haan and forward Cal Clutterbuck got hurt and weren't able to play against Washington.

Gibson, defensive call-up Scott Mayfield and journeyman forward Eric Boulton stepped up as New York lost defenceman Brian Strait to an upper-body injury but still managed to stay competitive.

"Our guys just battled, and I think that the guys that were in there tonight were resilient," Capuano said. "Even when we were down 3-1, we just had the confidence and we felt it coming."

Capitals coach Barry Trotz could sense it, too. He said it was "uncharacteristic" of his team to blow a third-period lead because it hasn't happened much this season. The Capitals lost back-to-back games for just the fourth time this season.

Fans are "not used to us giving up a lead, so it feels a little weird," Trotz said.

The Capitals have nothing left to play for except getting Holtby the record. He allowed four goals on 27 shots to remain stuck on 47 wins with three games left. Even though there were defensive miscues in front of him, Holtby blamed himself.

"We played a good enough game to win tonight," Holtby said. "That one's on me, and it's one of those ones I'll make up for in the future."

That future is the playoffs, where the Capitals will have home-ice advantage throughout. The Islanders will likely start on the road but are happy to be in.

Earning that playoff ticket was a source of motivation for the Islanders, who beat Tampa Bay at home on Monday night. Holtby's record was on the minds of the Capitals, but that didn't extend to the visitors' side.

"Who, Holtby? I think it's more we want to make the playoffs," said Tavares, who scored his 31st goal of the season. "We knew we get a win, we're in. ... Winning always feels good."

NOTES: Capuano had no update on Strait and said he was tired of talking about injuries. ... Capitals C Nicklas Backstrom missed his third consecutive game with an undisclosed upper-body injury.