Jalen Brunson and OG Anunoby each scored 29 points as the New York Knicks rallied from a 20-point deficit to defeat the Boston Celtics 108-105 in overtime on Monday night, taking a 1–0 lead in their Eastern Conference semifinal series.

The Knicks had been swept by Boston during the regular season but flipped the script at TD Garden in Game 1 with timely shot-making and late-game execution.

Boston appeared in control after building a 75-55 lead midway through the third quarter, but New York responded with a 20-9 run to close the period and cut the deficit to single digits.

The Knicks opened the fourth quarter with eight straight points, tying the game at 86 after Anunoby’s steal and dunk in transition.

A back-and-forth final stretch saw both teams trade leads, with Derrick White’s corner three giving Boston a 98-97 edge before Anunoby answered with one of his six triples.

Brunson had a chance to win it in regulation but missed a short bank shot, and Jayson Tatum’s contested jumper at the horn was off.

In overtime, New York surged ahead 106-100 after Anunoby converted a three-point play and Mikal Bridges knocked down a corner three.

Jaylen Brown hit his only three-pointer of the game to trim the margin to three with just over a minute remaining.

After Josh Hart missed a deep three and Tatum’s jumper rimmed out, the Celtics had one final chance following a timeout with three seconds left.

On the ensuing inbounds, Bridges stripped Brown near the sideline to secure the win and stun the home crowd.

Towns contributed 14 points and 13 rebounds for New York, while Hart added 14 points and 11 boards.

The Knicks shot 45.9 percent from three-point range, making 17 of 37 attempts, compared to Boston’s 15-for-60 performance from deep — a new NBA playoff record for most missed threes in a single game.

Tatum and Brown led the Celtics with 23 points each, though Brown went just 1-of-10 from long range.

White added 19 points and 11 rebounds, and Jrue Holiday returned from injury with 16 points in 39 minutes.

Boston center Kristaps Porzingis played just under 13 minutes before leaving the game due to illness and did not return after halftime.

Game 2 is scheduled for Wednesday night in Boston.