The Celtics were tied at 96 with the Pacers Monday night in Indiana. With a 4.6-second differential between the game and shot clocks, they were guaranteed another shot after the Pacers’ possession.

Pascal Siakam set a pick on Derrick White, who stumbled to the ground to cause a switch onto a 6-foot-8 Siakam on the wing. Siakam backed White down to the free throw line, eventually spinning to make a floater in the lane that yielded a 98-96 advantage for the Pacers.

Joe Mazzulla was irate. He screamed at the officials from his sideline, pleading his case for an offensive foul on the screen Siakam had set. The NBA later agreed with Mazzulla, explaining in its last two-minute report Siakam had not established himself making his screen illegal.

It was too late. What mattered Monday night was the Celtics’ two-point deficit with 5.1 seconds on the clock.

With Jaylen Brown missing the game due to back spasms, Mazzulla used a timeout to advance the ball to the Celtics’ offensive end and to draw up a potential go-ahead game winner. White inbounded the ball to Sam Hauser, who dished it back to White before setting a pick. White dribbled to the opposite wing, where his tightly contested 32-foot jumper clanged off the back iron, leading to the Celtics’ 98-96 loss to the Pacers.

How did Mazzulla explain the Celtics’ late-game outcome?

“Illegal screen,” said Mazzulla, who uttered the comment a total of six times during his 40-second postgame press conference.

It was the latest example of the Celtics complaining about a lack of foul calls, occurring hours after Brown was fined by the NBA for his comments after Saturday’s loss to the Spurs about an alleged lack of foul calls against top opponents.

“You do everything you can to control not being in those situations,” Mazzulla said on Zolak and Bertrand Wednesday. “So I thought we played a great first half. If you take a look at that third quarter where they went on, they ended up going up 13. We just obviously weren’t great from an execution standpoint, whether that’s offensively or defensively. So you get down 13 to a team like that, especially at home, they have the ability to go on runs there and then I think that’s where late game is a product of those runs throughout the game that we have to do a better job managing.”

But even with a disagreement with the official’s whistle, the Celtics still had an opportunity to escape Indiana with a win. Instead, they got the ball to White for a deep 3-pointer off his dribble, an aspect of his game that he has been forced to adapt to in 2025-26.

White finished Monday’s game with 18 points on 7-of-21 shooting, including a 2-of-9 mark from deep. Finding a rhythm from behind the arc has been major issue for White, whose 33.1 3-point percentage this season is currently the second worst clip of his career.

Throughout White’s nine professional seasons, he has thrived on catch-and-shoot 3-pointers by nailing 1.3 of his 3.5 attempts in his career. That mark has diminished to 1.3-for-4.4 in 2025-26, resulting in what would be the lowest since he was traded to Boston in 2022. A year ago, White was making 2.5 of his 6.0 catch-and-shoot 3-pointers.

Without Jayson Tatum on the floor, White has been forced to create more of his own shots. It has resulted in a decrease of catch-and-shoot 3-pointers and an increase of pull-up jumpers. He is averaging 5.2 pull-up 3s per game — beating out his previous career-high of 3.0 from 2024-25 – while sinking only 1.9 of those shots.

“He’s continuing the same effort and energy on both ends of the floor,” Mazzulla said after the Celtics’ 126-105 win over the Lakers on Dec. 5. “I think as we continue to evolve offensively and play with the level of pace and execute and work the reads that we have he’s getting some catch and shoot shots.

“It was just the ability to just make a couple more catch and shoot shots. And once he was able to do that, you’re seeing the consistency that he has.”

Given the circumstance of how a pull-up jumper occurs during a possession, it is unlikely to lead to an assist from a teammate. It is a direct correlation to White’s 63% assisted 3-point rate, which is a stat by Cleaning The Glass that measures how many made shots resulted in an assist for a teammate.

White’s assisted 3-point rate has never been below 80% in his career, until this season.

Mazzulla clarified his comments with Zolak and Bertrand on Wednesday, explaining that the Celtics need to get better on a possession-to-possession basis to win games that are similar to Monday’s in Indiana. They shot only 25.7% on 3-pointers and turned the ball over 12 times while generating just 22 assists. Some key areas Mazzulla and the Celtics must improve on.

“The message to our team is control the possessions that we have to get better at so we’re not in those situations,” Mazzulla said. “So that’s kind of, that’s the film today. That’s what the practice plan will be built around.

“It wasn’t the main reason for the outcome of the game. There’s about 15-20 things that we could do better so that we’re not in those situations, and that’s what we’ll focus on in practice today.