Nikola Jokic had 42 points and 22 rebounds, and Aaron Gordon hit a 3-pointer in the closing seconds to give the Denver Nuggets a stunning 121-119 comeback win over the top-seeded Oklahoma City Thunder on Monday night in Game 1 of their Western Conference semifinal series.

Oklahoma City, out of timeouts, missed a desperation heave as time expired.

Denver’s Russell Westbrook, who started his career with the Thunder, assisted on Gordon’s game-winner. It was his first playoff game in Oklahoma City as an opposing player.

Gordon finished with 22 points and 14 rebounds. Jamal Murray added 21 points for the fourth-seeded Nuggets, who stole the opener after closing out a seven-game series against the Los Angeles Clippers on Saturday.

Denver’s opportunity came after Oklahoma City’s Chet Holmgren missed two free throws with the Thunder leading by a point.

Shai Gilgeous-Alexander had 33 points, 10 rebounds and eight assists for the Thunder, who hadn’t played in more than a week after sweeping the Memphis Grizzlies in the first round. Alex Caruso added 20 points, six assists and five steals

Knicks 108, Celtics 105 (OT): The Knicks grew accustomed to facing big deficits against the Celtics this season.

New York faced another one to open its Eastern Conference semifinal matchup against the defending NBA champions. This time, the Knicks found a way to overcome it and win at Boston.

Jalen Brunson and OG Anunoby each scored 29 points before Mikal Bridges stole the ball from Jaylen Brown with a second left in overtime, and the Knicks stunned Boston in Game 1 of their series.

Karl-Anthony Towns added 14 points and 13 rebounds for New York, which lost all four games against its longtime rival during the regular season and trailed by 20 points in the second half of this game.

Jayson Tatum and Brown both had 23 points for the Celtics, who had an NBA playoff-record 45 missed 3-pointers to blow a game they appeared to have in control. Derrick White added 19 points and 11 rebounds.

Jrue Holiday returned to the starting lineup after a strained right hamstring caused him to miss the final three games of Boston’s first-round series against Orlando. He finished with 16 points in 39 minutes, but center Kristaps Porzingis played only 13 minutes and didn’t return after halftime because of an illness.

Game 2 is Wednesday night.

Cavs’ Atkinson is NBA Coach of the Year: Kenny Atkinson went through a winless preseason with the Cleveland Cavaliers and wondered if his team would be any good.

Turns out, they were better than good.

And their coach — he was the NBA’s best this season.

Atkinson is now an NBA Coach of the Year winner, announced Monday night as this year’s recipient of the Red Auerbach Trophy. Atkinson led Cleveland to a 15-0 start to the season — one of three winning streaks of at least 12 games this season by his club — and led the Cavaliers to the best record in the Eastern Conference.

“I stepped into this,” Atkinson said. “I keep saying that, that I stepped into this. It’s a little bit of luck too, right?”

J.B. Bickerstaff was second in the voting, after pulling Detroit from the basement to the playoffs. Ime Udoka was third, after guiding Houston’s path to ending its five-year playoff drought.

All three did elite jobs this season. But none better than Atkinson.