WASHINGTON -- Nobody could have envisioned Christopher Gibson being the New York Islanders goaltender on the night they would clinch a berth in the 2016 Stanley Cup Playoffs.
Gibson, the No. 4 goalie on the Islanders depth chart, got the call Tuesday with injuries to Jaroslav Halak and Jean-Francois Berube, and Thomas Greiss playing the previous night. But Gibson looked like he belonged in his first NHL start, making 29 saves, and Thomas Hickey scored at 2:13 of overtime in New York's 4-3 win against the Washington Capitals at Verizon Center.
John Tavares, Kyle Okposo and Anders Lee scored and Gibson made 29 saves for the Islanders (44-26-9), who will be in the playoffs for the third time in four years.
"He played extremely well for us," coach Jack Capuano said of Gibson, who was recalled from Bridgeport of the American Hockey League on an emergency basis Monday after Berube sustained a lower-body injury. "It just shows the confidence and poise that he has. He gave us a chance to win the game, and he was our best player tonight."
Video: NYI@WSH: Hickey's goal sends Islanders to playoffs
The Islanders needed two points against the Capitals or a Boston Bruins loss against the Carolina Hurricanes to secure a playoff spot, and they wanted to do it on their terms.
"It's the hard way," Hickey said. "We didn't wait for someone else to do it for us. To come in here in the back end of a back-to-back and have some guys step up like [Gibson] 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."
Alex Ovechkin had two goals and T.J. Oshie scored for Washington (55-18-6). Braden Holtby made 23 saves in his 64th game. He remains two wins shy of passing Martin Brodeur (48) for the most wins in a season. The Capitals have three games remaining.
Video: NYI@WSH: Ovechkin scores twice against the Islanders
"I feel like we play for each other every night in this room," Holtby said. "That's why we've had so much success. We played a good enough game to win tonight. That one's on me, and it's one of those ones I'll make up for in the future."
Ovechkin opened the scoring at 4:29 of the first period. Off a faceoff win by Marcus Johansson, Ovechkin controlled the puck into the corner and scored his 46th goal of the season at a tight angle.
Tavares tied the game at 13:43 of the second period when he scored on the rush from the high slot off a pass from Hickey. Tavares' shot bounced off the tip of Holtby's glove.
Video: NYI@WSH: Tavares one-times it past Holtby to tie game
"They're a good team," Holtby said of the Islanders, who pushed Washington to seven games in the opening round of the 2015 postseason. "We saw them last year obviously in the playoffs, and they haven't changed much. They're a tough team to play against. They're banged up and they're still a pretty good team. Every team is good in this League."
Oshie scored at 1:15 of the third period to give the Capitals a 2-1 lead. Johansson whiffed on a pass to Oshie in the right circle, where Oshie scored his 26th goal of the season.
Ovechkin scored his second goal of the game at 6:56 of the third period, his 47th of the season.
But Okposo got the Islanders within a goal at 8:40 and Lee tied the game with his 15th goal of the season at 10:25.
Video: NYI@WSH: Okposo reacts the quickest to strange bounce
"We just wanted to keep our foot on the gas," Okposo said. "We didn't want to get discouraged when they scored. I thought we were playing a pretty good hockey game. They got a couple goals, but we didn't quit and we knew we were still in the game. We just wanted to keep fighting, and we did."
Capitals forward Nicklas Backstrom missed his third consecutive game because of an upper-body injury.
Islanders defenseman Brian Strait sustained an upper-body injury and did not play after the second period.
Video: Isles clinch playoff berth with OT win over Caps