Boston guard Malcolm Brogdon drives to the basket against Indiana’s T.J. McConnell, right, during Wednesday’s game in Boston. Charles Krupa/Associated Press

BOSTON — Tyrese Haliburton scored 33 points and the Indiana Pacers opened a 30-point lead in the first half before holding off the slumping Boston Celtics 117-112 on Wednesday night.

Former Celtics player Celtic Aaron Nesmith had 15 points, Chris Duarte added 14 and Myles Turner had 10 to help the Pacers win for the fourth time in five games.

Jayson Tatum led Boston with 41 points after missing a game because of personal reasons, while point guard Marcus Smart sat out with a non-COVID illness. Jaylen Brown added 19 points and 10 rebounds for Boston, and Malcolm Brogdon had 18 points. Atop the NBA a week ago, the Celtics have dropped three straight games and five of six.

Coming off consecutive home loss to Orlando, the Celtics fell behind by 30 points late in the second quarter before Tatum carried them back into it.

Indiana led 71-43 at the half, and the Celtics walked off the court to a spattering of boos echoing down from the fans at TD Garden.

Tatum’s 3-pointer from the right wing cut Boston’s deficit to seven points midway into the final quarter. Brown’s 3 made it 111-106 a few minutes later but Haliburton answered with a 3 from the top the next trip down the floor and the Pacers closed out the victory.

The Pacers led by 19 points at the end of the first quarter and used an 11-0 run midway into the second, pulling ahead 59-30 before Nesmith’s 3 from the left corner gave them their first of three 30-point leads late in the opening half.

NOTES: Tatum had a powerful dunk over former teammate Nesmith and let out a loud yell looking at the Pacers forward when he was fouled on the play. … Duarte banked in an off-balance 3-pointer from deep on the left wing as the third-quarter buzzer sounded, giving the Pacers a 100-85 lead. … The Pacers had a season-high 42 points in the first quarter when they shot 61.5% (16 of 26) and connected on 8 of 11 from 3-point range. … Boston’s Brown went tumbling over a TV table at midcourt early in the game but got right back up. … Three Boston starters (Al Horford, Derrick White and Payton Pritchard) were scoreless in the first half.