David Butler II-Imagn Images

Celtics Coach Doesn't Hide His Frustration Over Loss to Pacers

Originally posted on Athlon Sports | By Reign Amurao | Last updated Jan 13, 2026 12:23 AM ET

The Boston Celtics tried their best against the Indiana Pacers, a team that's at the bottom of the Eastern Conference, on Monday. The Celtics were without All-Star forward Jaylen Brown, who was out with lower-back spasms. Without their star player, the team suffered a 98-96 loss.

The game was close, and it came down to the wire. On the Pacers' final play, the team forced Pascal Siakam to switch onto a smaller defender, Derrick White. Siakam had a greater edge because of his size, even though the Celtics guard is an excellent perimeter defender.

The Pacers star posted up on White and shot a floater to give them a two-point lead. The Celtics couldn't generate anything with 6.1 seconds left in the game.

Boston Celtics coach Joe Mazzulla.David Butler II-Imagn Images

Following the game, Celtics coach Joe Mazzulla was asked about his thoughts on Siakam's game-winning shot. Mazzulla did not hold back and just answered with "illegal screen." Throughout his availability with the media after the game, he kept repeating the two words to answer all six questions he received.

Joe Mazzulla answered every single question with “illegal screen” pic.twitter.com/Qx6Sioyre6
— Fullcourtpass (@Fullcourtpass) January 13, 2026

Mazzulla feels strongly that the star forward committed an offensive foul before getting the ball. Boston is now 2-3 over the past three games. Furthermore, this is not the first time a Celtics player has expressed dissatisfaction with the officiating.

Last Saturday, Brown criticized the officials for the wide discrepancy in foul calls they received in their 100-95 loss to the San Antonio Spurs. Following that, the 2024 Finals MVP was fined $35,000 by the NBA. The Celtics only had four attempts at the free-throw line, while the Spurs had 20.

The Celtics will continue their four-game road trip on Thursday and will face the Miami Heat.

This article first appeared on Athlon Sports and was syndicated with permission.

More must-reads: