The Celtics are not shrugging off their disastrous fourth quarter against the Cavaliers

BOSTON -- It looked like the Celtics were well on their way to a 12th straight win in Cleveland on Tuesday night, holding a 22-point lead over the Cavaliers early in the fourth quarter. But they put things on cruise control, and by the time they tried to get a foot back on the gas pedal, it was too late.

Before the Celtics knew it, they were walking off the floor following a disappointing and chaotic 105-104 defeat to the undermanned Cavaliers. It's a feeling the Celtics haven't had to deal with for a while, but one that will certainly stick with them.

For 40 minutes on Tuesday night, the Celtics looked like the Celtics that had dominated their competition over the last 11 contests. Another double-digit victory was in their grasp, before the Celtics completely let go of the rope in the fourth quarter. The Cavaliers, who were without Donovan Mitchell and Max Strus, rattled off a 34-11 run over the final nine minutes and outscored Boston 34-17 in the fourth to stun the Celtics.

It led to a turbulent final minute, with the Celtics defense losing Dean Wade (a common trend in the quarter) and letting the forward slam home a Darius Garland miss with 19 seconds left to give the Cavs their 105-104 edge. Joe Mazzulla did not call a timeout (at least at first) and let his team dribble down the floor, only to have Jayson Tatum waste most of the time before attempting a game-wining jumper with 0.7 seconds left.

Tatum missed, and though Kristaps Porzingis was there for a potential game-winning putback, a foul call on Garland negated that bid. It was going to put Tatum at the line for a chance to win the game, but the Cavaliers challenged the call and officials ruled that Tatum's leg kick caused the contact with Garland.

So no freebies for Tatum. And the Celtics had the impossible task of winning a tip at midcourt and throwing up a desperation shot with less than a second on the clock if they wanted to steal the win back from Cleveland. Porzingis won the tip, but by the time Derrick White got the ball in his hands, that 0.7 had ticked off the clock and Boston didn't even get a last-second heave. 

Everything about the fourth quarter was a disaster for the Celtics. An absolute disaster. Mazzulla said that he tried to call a timeout with 4.6 seconds left but the officials didn't hear or see him. First, he shouldn't have waited that long, because it was painfully obvious to anyone watching that the Celtics were still moving in slow motion and Tatum was going to take his sweet time with the final possession. Second, Mazzulla should have been doing cartwheels on the floor to get that timeout. 

But really, it never should have gotten to that point in the first place. And the Celtics have no one to blame but themselves.

The Celtics were abysmal both offensively and defensively in the final quarter. They shot 30.8 percent for the fourth and missed all eight of their 3-point attempts. Tatum played all 12 minutes and was just 1-for-9 for two points. Jaylen Brown scored 12 of his 21 points in the third, but didn't attempt a shot and went scoreless in his 5:14 on the floor in the fourth.

It looked like the Celtics were lulled to sleep in the final frame. And while their bricks piled up, the Cavaliers kept hitting shot after shot after shot. Cleveland was 11-for-15 overall and 8-for-11 from 3-point range in the fourth, knocking down 10 straight over a 10 minute stretch. Of those 10 makes, eight of them were from downtown.

The Celtics either lost Wade behind the arc or got caught with a big man defending the forward throughout the quarter, and he absolutely torched them. He dropped 20 points in the frame, going a perfect 7-for-7 from the floor and 5-for-5 from deep.

This is not how Boston wanted to start its five-game road trip. But it was a humbling evening for a team that had blowing out its opposition with ease lately, and they'll be feeling the sting for at least a few nights.

The Celtics have done a good job at moving on this season, but they will not overlook Tuesday's loss. 

"Today matters. Whether everybody wants to throw it away or not, we've gotta look at the film and address some stuff because that matters," said Brown. "Your habits are everything. Your mentality is everything. Every game, you can't waste possessions, time out there on the floor. Today matters. We need to look at that."

Brown termed the defeat as a "mentality loss."

"Everybody is gonna have their perspective on it. Mine is, that's what happens when you don't match the gas and take little things for granted throughout the game, and you let a team stick around," he said. "They're still NBA players. Tip your cap to Dean Wade. He got hot. We weren't expecting that, but we still should've won this game."

Let's make one thing clear: The sky is not falling for the Boston Celtics. They've been the NBA's best team all season, and don't forget the dominance that they just displayed for a month straight. Don't overreact to all that winning, but also, don't overreact to a single loss. It was a painful loss, absolutely, and the Celtics did it to themselves. But it's still just one loss. 

Tuesday night was a good reminder that the Celtics are still capable of dropping games, something they've only done 13 times this season. Now they'll see if they can remember how to bounce back from a loss, which they haven't had to do in over a month.

"This year, we've done a really good job of responding," said Tatum. "I look forward to us responding and playing better on Thursday."

The Celtics are the best team in the NBA at bouncing back, touting an 11-1 record following a loss, and they haven't lost two straight since early November. They'll look to continue that trend -- and try to start a new streak -- Thursday night when they visit the defending champion Denver Nuggets.