Mazzulla Fumes After Siakam’s Buzzer-Beater Sinks Short-Handed Celtics

The Boston Celtics walked off the floor in Indiana with more than a loss to digest. In the closing seconds of a tightly contested game, Pascal Siakam shook free for a winning basket, leaving Boston without enough time or rhythm to answer on the other end. For head coach Joe Mazzulla, the final possession was not simply a defensive breakdown—it was, in his view, a missed call that decided the outcome.

Mazzulla, now midway through his fourth season at the helm, has spent this year adjusting on the fly. A reshaped roster and the continued absence of Jayson Tatum, who remains sidelined while rehabbing his Achilles, have forced Boston to rely on depth and discipline rather than overwhelming talent. The Celtics have stayed afloat in the playoff picture, but nights like this expose how fragile their margins have become.

That vulnerability was on full display against the Pacers. Boston had chances to seize control late, but its final offensive possession stalled, allowing Indiana one more look. Siakam delivered, curling off a screen and rising for the game-winner that silenced the visiting bench.

Afterward, Mazzulla did not cloak his frustration in diplomacy. Asked repeatedly about the decisive play, he offered the same two words to nearly every question: “Illegal screen.”

1. Two Words, Six Questions

Mazzulla’s postgame news conference lasted barely longer than the final possession that prompted it. Each time reporters pressed him on the mechanics of the play, the coach returned to the same phrase, unwavering in his belief that Siakam’s path to the basket had been improperly cleared. The bluntness of his response spoke volumes. Coaches are trained to deflect, to keep their critiques general, but Mazzulla opted for a rare show of directness. The screen, he felt, was not just questionable—it was decisive, altering the outcome of a game that had been balanced on a knife’s edge. From Boston’s perspective, the sequence compounded an already frustrating night. The Celtics had defended well enough to stay in contention despite missing key contributors, yet one unwhistled moment proved enough to undo 47 minutes of effort. Whether the league office will see it the same way remains to be seen. But for Mazzulla and his players, the feeling was immediate and visceral: an opportunity lost, and a lesson reinforced about how little room they have for mistakes.

2. Competing Without the Core

The Celtics entered the contest missing Jaylen Brown and continuing to wait on Tatum’s return, leaving Mazzulla to piece together lineups heavy on role players. To their credit, Boston did not retreat into survival mode. They traded punches with Indiana for most of the night, keeping the game within reach until the final horn. Payton Pritchard shouldered the scoring load, finishing with 23 points to go with eight assists, four rebounds, and two steals. His aggression off the dribble kept Boston’s offense afloat, particularly during stretches when the Pacers threatened to pull away. Derrick White added 18 points and five assists, while Anfernee Simons and Neemias Queta chipped in 16 and 15 points respectively. It was a collective effort rather than a star-driven one, reflective of how Boston has had to survive this season. Yet the absence of their primary creators loomed large in the final minute. When the Celtics needed a clean look, they struggled to generate separation, a contrast to Indiana’s ability to free Siakam when it mattered most.

3. Perimeter Gaps and Playmaking Edges

Beyond the disputed call, the box score revealed why Boston was chasing the game in the closing moments. Indiana controlled the perimeter, knocking down 16 three-pointers to Boston’s nine, a disparity that steadily tilted the scoreboard. The Pacers also moved the ball with greater purpose, recording 29 assists compared to the Celtics’ 22. That extra layer of connectivity showed up late, when Indiana found its best option under pressure while Boston labored to find any. The loss dropped the Celtics to 24–15, good for third in the Eastern Conference. They sit one game ahead of Toronto and a game and a half in front of Philadelphia, but now trail the New York Knicks by one game and the Detroit Pistons by 4.5. In a tightly packed conference, nights like this resonate well beyond a single result. Boston will not have long to linger on the frustration. The road trip continues with a matchup against the Miami Heat on Jan. 15, another test for a team still searching for stability while its stars remain unavailable.