The Celtics lost a tight contest to the Pacers on Monday night. Traveling to Indiana without MVP candidate Jaylen Brown, who was ruled out with back spasms, Boston fell behind in the first half thanks to a hot shooting night from the opposing side but closed the gap down the stretch. The Pacers pulled out the win, though, as Pascal Siakam hit a floater over Derrick White with six seconds remaining to move to 9-31 on the season.
Celtics coach Joe Mazzulla quickly made it clear after the game that he was not pleased with how Siakam’s final shot was officiated. After sitting down to speak with media postgame, Mazzulla called out the refs by answering every question with one simple response: “Illegal screen.”
joe mazzulla answering every question “illegal screen” pic.twitter.com/SCnuXLXW3B
— JGFC (@JGFC__) January 13, 2026
While Mazzulla (obviously) did not expound upon his thoughts, it seems most likely he’s calling out the lack of an illegal screen call on the Pacers’ final possession. In the below clip of Siakam’s go-ahead bucket, he sets a screen on White to force the smaller guard to switch onto him. As soon as it happens Mazzulla motions to the closest referee and wants to know why there wasn’t a foul. The refs let the game go on and Siakam took full advantage of the switch to earn the win.
PASCAL SIAKAM WITH THE CLUTCH BUCKET TO PUT THE PACERS UP TWO! pic.twitter.com/QgoAOEOvzk
— TSN (@TSN_Sports) January 13, 2026
NBA officials tend to tighten the whistle in the final minutes of a close game and in particular very rarely call illegal screens. Siakam’s example above is not the most egregious illegal screen refs have let go in the last minute of the fourth quarter. But it does appear to fit the definition of an illegal screen, with Siakam moving up the court as he makes contact with White to force the switch.
It’s another night in which Boston’s main figures have expressed frustration with the referees. Shortly before tip-off on Monday night Brown received a hefty fine (after daring the NBA to do so) following an unhappy rant about the lack of foul calls his team got in a similarly close loss to the Spurs. The fact that a different call might have swung the outcome of both games surely adds to the frustration shown by Brown then and Mazzulla tonight.
We’ll see if the NBA decides to punish the Boston head coach for his thinly-veiled criticism of the referees. In the meantime the 24-15 Celtics will try to snap their two-game losing streak against the Heat on Thursday night.
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This article was originally published on www.si.com as Joe Mazzulla Slammed Refs by Repeating One-Liner After Celtics’ Tough Loss to Pacers.
