CLEVELAND — The Nets played a back-to-back at the NBA’s reigning champions and it’s only unbeaten. They led both late, before falling agonizingly short in both.

A night after an overtime defeat in Boston, the Nets suffered a heartbreaking 105-100 loss to Cleveland before a sellout crowd of 19,432 at Rocket Mortgage Fieldhouse.

The Nets (4-6) led by seven with 4:09 to play before committing three costly turnovers to hand the Cavaliers a 10-0 run that essentially decided the contest.

And in their first matchup with Kenny Atkinson as a head coach since firing him in 2020, the Nets saw their own new rookie coach take the blame for this defeat, outscored 35-18 in the fourth quarter.

“That’s not how you close games in this league on the road against a very good team. Like I told the guys, it is my fault,” coach Jordi Fernandez said. “I ran Dennis [Schroder] 12 minutes in the fourth. I didn’t give him a break. That’s how your execution goes down. That’s how your defense goes down.

“I didn’t give Cam Thomas breaks. And then at the end, we paid for it. So I have to be better with my subs, being cleaner with the calls of the end, and we have to execute and hit the shots. Once again, 20 turnovers on the road for 26 points, that cost us the game.”

Cam Johnson (game-high tying 23 points) had hit a 3 to give the Nets a 96-89 lead with 4:24 left. But they allowed 10 unanswered points, sparked by three quick turnovers from Thomas, Schroder and Nic Claxton, the latter pair playing the entire fourth quarter on the tail end of a back-to-back.

“[It’s] how you open the game and how you finish the game. So once again, we [have] got to be better,” Fernandez said. “I have to be better with giving those guys breaks so they feel fresh at the end. Tell them exactly what to do and control and get good shots, and we didn’t. I’m proud of the guys in the fight.”

Schroder — who had 22 points and five assists in a marathon 37:25 — hit two free throws to get them back to 99-98 with 1:39 to play. But Darius Garland’s jumper put them back in a three-point hole.

Thomas (22 points) hit a tough baseline fade to pull the Nets within 101-100, but Ty Jerome made it three again.

And when Schroder missed a potential tying 3-pointer with 27.8 seconds left in regulation, there would be no overtime this time.

“The last four minutes, we were up seven. And I think we’ve got to improve, me organizing the team, taking the shots we really want,” Schroder said. “We’ve just got to be better executing. On the defensive end we’ve got to take pride in one-on-one defense. They can’t beat us that easy for three floaters in a row.”

Johnson led the Nets with a game-high tying 23 points. His sixth straight turnover-free 30-minute game tied an NBA record, and he was the first to do it with multiple 3s.

Evan Mobley had 23 points for the Cavs (11-0), while added Donovan Mitchell added 22 and Garland 20.

“I just want to give them a ton of credit. They played a great game,” Atkinson said of the Nets. “Credit Jordi. He’s doing a great job. They are obviously exceeding expectations, so just wanted to get that out there.”

For his part, Schroder wouldn’t use fatigue as an excuse.

“That’s not an excuse. I mean, it’s whatever it takes. I think we could’ve ran better set plays for us to execute, and that’s on me. I don’t know if it’s all coach, but I’ve got to make sure we’re still playing with pace, doing the right things,” said Schroder, though he added Fernandez taking responsibility and falling on the proverbial sword meant a lot to his Nets.

“I love that. I love that. He’s not shying away from it. That’s the vibe he gave us in training camp as well; nobody’s perfect. That he’s saying that, you know, it means a lot to us as well. But it’s us who played the last 4 ½ minutes, and we’ve got to look, everybody’s got to look in the mirror and get better from it and grow from it.”