After leading for most of Sunday’s road game against the Cleveland Cavaliers, the Boston Celtics found themselves in a nailbiter after squandering most of their big second-half lead. The Cavaliers nearly erased a double-digit deficit in the fourth quarter, trimming the Celtics’ advantage to just two points. They also held the ball for the final possession with 0.6 seconds left and a chance to either tie or take the lead. Meanwhile, Boston was running on fumes on the second night of a back-to-back. It was also short-handed without Derrick White, Neemias Queta and Jayson Tatum. With the Celtics up 117-115 and needing a stop to win the game, Joe Mazzulla got creative. He subbed in rookie big man Amari Williams, who was called up from the G League earlier in the week to help replace Queta. Although Williams had only played six minutes on Sunday, he was ready for the biggest moment of the game. Right before Donovan Mitchell inbounded the ball from the sideline, he switched onto Evan Mobley, who led Cleveland with 27 points and 14 rebounds. Story continues below advertisement Here's the play Joe's talking about.Amari Williams comes off the bench for the final possession, stays with Evan Mobley all the way out to the arc, and perfectly contests the shot without fouling. Returns to the bench for some well-deserved high 5s.https://t.co/brY6d1KKxv pic.twitter.com/RsSrzxoErI— Taylor Snow (@taylorcsnow) December 1, 2025 Mobley caught the ball just inside the 3-point arc at the top of the key, quickly turned around and fired the potential game-tying shot. Williams was right in his face, however, denying him a clean look at the basket. Mobley’s shot wasn’t close, missing everything as time expired. Story continues below advertisement After the game, Mazzulla praised Williams for his attention to detail and strong close-out with the game on the line. “Amari not playing in the game and having to go in in a need-two situation, like you don’t understand how important those details are,” Mazzulla told his team after the game. “Every possession gives you a chance, and you end up guarding the guy on that last play. But hey, that’s a great mindset win.” Williams has only played 28 minutes for Boston this year, so he hasn’t had much of a chance to make an impact. But during one of the most critical moments of the season so far, he delivered. Story continues below advertisement