The Boston Celtics had everything going their way—until they didn’t. Up by 22 points in the first quarter, the game looked like another routine win for the Eastern Conference leaders. But then the Cleveland Cavaliers stormed back, flipping the script and stunning Boston with a 123-116 comeback victory.

It wasn’t just a loss—it was a collapse. And after the game, veteran big man Al Horford gave an honest assessment of what went wrong. Meanwhile, Jayson Tatum’s early celebrations only made the Celtics’ downfall even more painful.

For the Celtics, this game was yet another reminder of a recurring problem: building big leads, then letting them slip away. Horford didn’t shy away from addressing the issue, admitting that the team sometimes gets too comfortable when ahead.

“There’s naturally—you know—we can relax a little bit,” Horford said postgame. “Obviously, the other team’s not going to keep playing that bad. They’re going to make some plays. We’re going to make a run. But, yeah, definitely being able to try to keep those leads as best we can.”

Friday night saw his words ring true. In less than 15 minutes, the Celtics jumped to an insurmountable 25-3 lead, overwhelming Cleveland to a finish. The Cavaliers hadn’t played that bad, they didn’t keep playing it, as Horford predicted. A nightmare start, in fact, turned into a statement win for Cleveland, with Donovan Mitchell leading the way with 41 points, 12 of which came in the fourth quarter.

The Celtics meanwhile looked a team who took their foot off the gas too soon. Yet despite Jayson Tatum’s monster 46 points, 16 rebounds, nine assists display and Jaylen Brown’s 37, Boston couldn’t get it done.

Jayson Tatum’s Celebration Backfires as Celtics Suffer Embarrassing Loss

But toppling their 22 point lead with a mere bad finish wasn’t bad enough — Celtics fans had to endure another layer of embarrassment. At one point early in the game when Boston was dictating play, Tatum and Brown were seen taunting their opponents throwing up their “F*** outta Here” gesture as if the game was already over.

Fast forward to the final buzzer, and those same Cavaliers were celebrating on Boston’s home floor. The Celtics, once confident and in control, walked off in silence, their own arrogance coming back to haunt them.

It’s a brutal lesson—one that Horford, the veteran presence in the locker room, has likely seen too many times before.

While the Celtics’ defensive collapse played a huge role in their downfall, Jaylen Brown pointed to one specific moment that he believed changed the game.

“I think that changed the game”. Brown said about a fourth-quarter offensive foul that sent him to the bench. “I got an offensive foul called on a rebound. I feel like it was just in the paint fighting for the basketball, and it kind of just shifted the game for sure.”

Brown—who finished with 37 points on 13-of-24 shooting—felt the call was unfair, saying, “I don’t think it was a foul, I don’t think it was an offensive foul. When these little guys just fly up, they’re inclined to call it.”

By the time Brown returned, Boston had already surrendered momentum, and Cleveland never looked back.

This wasn’t just another loss—it was a statement game that exposed one of Boston’s biggest weaknesses. The Celtics are an elite team. The tendency to relax with big leads continues to haunt them. Against a battle-tested playoff opponent like the Cavaliers, it cost them dearly.

Now, Boston has no time to dwell on the loss. Up next? A matchup against the Denver Nuggets. If the Celtics don’t learn from this collapse, things could get even worse.