Jalen Brunson and OG Anunoby each scored 29 points before Mikal Bridges stole the ball from Jaylen Brown with a second left in overtime as the New York Knicks stunned the Boston Celtics 108-105 in Game 1 of their Eastern Conference semifinals series on Monday night at Boston.

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 defending champion 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 with 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.

The Knicks struck first in OT, taking a 106-100 edge via a three-point play by Anunoby, followed by 3-pointer by Bridges.

Brown connected on a 3-pointer from the wing with just over a minute left — his only make in 10 attempts behind the arc — to cut it to 108-105.

It stayed that way when Josh Hart misfired on a deep 3. Tatum missed a jumper, but the Celtics were able to retrieve the rebound. After a foul on Towns, Boston called timeout with 3 seconds showing on the clock.

But Bridges ripped the inbounds pass away from Brown to preserve the win.

The Celtics finished 15 for 60 on 3-pointers.

A wild end to regulation set up overtime.

New York cut what had been a 16-point halftime deficit to 84-75 entering the final period, thanks to a 20-9 run to end the third.

The Knicks kept it going, scoring the first eight points of the fourth quarter. They eventually tied it at 86 on a steal and dunk by Anunoby.

Atkinson selected NBA Coach of 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, a one-time assistant coach with the Warriors, 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.

All were coach of the year candidates previously.

The NBA Coach of the Year award, like several other honors, was voted on by a global panel of 100 writers and broadcasters who cover the league and cast ballots shortly after the end of the regular season.