CLEVELAND – Before Sunday night’s game against the Boston Celtics, Cleveland Cavaliers coach Kenny Atkinson said he wanted to see what his team would look like after two straight losses to the Atlanta Hawks – the first adversity they’ve faced this season .

Then, with the Cavaliers trailing by 14 in the third quarter, there was a feeling that Cleveland might be run out of its own building by the defending champions, who were without Jaylen Brown (illness) and Derrick White (foot).

“That was a little bit of my question mark with this team after the two losses to Atlanta,” Atkinson said later, “and it looked like we were devastated in the third quarter.”

“They were rolling, the crowd was kind of depressed, we were all kind of depressed.”

All Cavaliers, except Donovan Mitchell. Instead of watching the game slip away from him and Cleveland lose for the third straight time, Mitchell outpaced the Cavaliers, scoring 30 points in the second half – including 20 points in the fourth while going a perfect 6-0. 6 from the field – to beat Jayson Tatum down the stretch and help Cleveland to a 115-111 win.

“In the third,” Mitchell said when asked when he realized he had to take over the game. “I kind of felt it at the time, especially – and I’m going to be selfish when I say this – when (Tatum) put a shot over me.”

“I thought, ‘He’s starting to get it going, they’re starting to get confidence, they’re starting to build, we’re turning it around.’ …The third moment I was just waiting, trying to figure out where to go.

“And then when I came back in the fourth game, I was kind of like, ‘Okay, give me the ball. It’s time to go.’ And I just told someone, “No shots can be fired, I can go 0-for-6.” But you know what? You have to find a way to say, ‘I’m going to be aggressive here, and when we go out, this is what we’re going to do.’ And that’s exactly what happened tonight.

Mitchell said the third quarter reminded him of Game 3 of Cleveland’s Eastern Conference semifinal series against Boston, when the Celtics opened the third quarter with 14 unanswered points – putting the Celtics on track to win not just that game but the series win.

But unlike that game, when the Cavaliers lost, they battled back Sunday night, largely behind a standout performance from their leading man, who knocked down three triples in 93 seconds late in the fourth quarter to wipe out Boston’s lead and tied the game, then put Cleveland ahead with a runner in the lane with 1:07 left – a basket that gave the Cavaliers a lead they would never relinquish.

With the win, the Celtics maintained their best record in the NBA at 18-3, ahead of the Celtics at 16-4.

“That’s Donovan’s personality,” Atkinson said of how Mitchell brought Cleveland back into the game. “It’s amazing, I’ve never seen a guy (like him) before.

“It never goes down. You’d think the boys would kick the chair or get frustrated. He has a great demeanor and never stoops too low or too high. He’s much better than the coaches in that regard.”

“He just says, ‘Everyone calm down, everything will be okay.’ And I think that really helps you recover from such a bad first half.”

The Cavaliers also repeatedly allowed Darius Garland, their 6-foot-1 point guard, to go head-to-head with the 6-foot-8 Tatum, turning Boston into an isolation team and throwing the Celtics out of their usual ball calm. Movement is a serious offense.

It also worked when Tatum – who had 33 points, 8 rebounds, 4 assists, a steal and a block in just under 38 minutes – went 2-for-7 from the field in the fourth as Boston evaporated the lead.

“I mean, I worked on my spots all night long, attacking the mismatch and stuff like that,” Tatum said. “They probably started doubling down in the last four minutes. … So find someone who’s open and just try to make the right play.”

Atkinson said repeatedly during his postgame press conference that he challenged Garland to engage in defensive battles and said he didn’t want to hide from him in the playoffs. Garland said he was ready for it.

“I will accept this challenge whenever it is,” Garland said. “I’m not a punk. So if you all want to switch and try to trick me and just track me down, that’s cool. I’m not a punk though. I will accept a challenge.”

After starting the season 15-0, Cleveland’s challenge in this game was to stop the bleeding after losing three of their last five games.

And while there’s still a long way to go before a potential rematch with Boston in the playoffs, this was a game the Cavaliers could see as a sign of positive development.

“I think it speaks to the growth of our group,” Mitchell said of the comeback. “I think you go back to when I got here. Obviously we’re younger, we don’t know each other that well and we would kind of break down in those situations.

“You just see the growth, and I think the most important thing is that we just keep building… if we continue to grow and continue to learn from these different things, then that’s what it’s really about. That’s what it’s about tonight.’ We could have easily said, ‘Okay, turning the ball over, different things, not getting any stops, the offense kind of stalled.’ But who were we when faced with adversity? And that’s what I said. It’s great to learn from these victories, but who will we be when faced with adversity? . We tried games and different things and I’m proud of the way we fought.