WASHINGTON — The last time the Nets came to the nation’s capital they lost a huge lead and star Kyrie Irving. Wednesday it was a potential comeback victory that slipped through their fingers, fumbled away in a 110-106 heartbreaker with sloppy play their coach called ‘infantile.’

Sure, they blew coverage to leave Jerome Robinson open for a go-ahead 3-pointer. And Spencer Dinwiddie missed a step-back 3 on the other end to seal the loss at Capital One Arena.

But it was the 18 turnovers — 11 in the first half — that did the Nets in. It was an 18-point hole they dug for themselves that proved too much in the end, against a Wizards team they should have beaten if only their heads had been right.

“Focus. I’m really, I’m dumbfounded by how we weren’t mentally into the game. Not taking anything away from Washington but I mean there were just some infantile mistakes out there in terms of the turnovers,” Kenny Atkinson said. “You’ll have to ask the guys, I’m going to ask them. I’m not sure.

“I don’t think it was physical, I don’t think it was a game plan. It was pure focus. And we can all go into our dictionary or ask as a sports psychologist what ‘focus’ means or what ‘mentally locked in’ means, but we weren’t. It was evident that first half.”

The Nets — who’d rallied from 45-27 down — took a 106-105 lead on Dinwiddie’s driving layup with 24 seconds to play. But bent on not getting beaten by Bradley Beal (30 points), they let his gravity pull them out of shape in a box-and-one defense. It left Robinson wide open for a left-wing 3 that put Washington up with nine seconds in regulation.

The Brooklyn Nets fell to the Washington Wizards on Wednesday.
The Brooklyn Nets fell to the Washington Wizards on Wednesday.NBAE via Getty Images

“We were in a junk defense, box-and-one-type of defense, and there was a screen at the top. They overloaded the back side,” Caris LeVert said. “If we’d have talked better we probably would’ve matched up better.”

LeVert had a game-high 34 points, seven assists, six rebounds and four steals. But with the Nets wanting to avoid Beal — who was guarding LeVert — they put the ball in Dinwiddie’s hands for the final, fateful shot.

Dinwiddie got the switch he wanted, with Davis Bertans on him. But he settled for a step-back 3 that missed. Robinson grabbed the defensive rebound and iced it at the line on the other end. There would be no overtime, and no comeback.

For his part, LeVert — on fire since rejoining the starting lineup nine games ago — wasn’t disappointed Dinwiddie got the last shot. It was the turnovers and lack of focus he rued.

“That’s our job. We’ve got to come in locked in from the start, no matter who we’re playing, for a full 48 minutes. I feel like for stretches of the game we’ll have it, but not for a full 48 minutes,” LeVert said.

The Nets trailed 45-27 after a 3-pointer by ex-Net Shabazz Napier midway through the second quarter. They trailed 60-47 after a sloppy first half that saw them cough up the ball 11 times.

The Nets turned the tide with a 37-21 third quarter. Trailing 69-59 after an Ian Mahinmi dunk, the Nets reeled off nine unanswered points to climb within one on a DeAndre Jordan dunk.

Garrett Temple’s 3 put them over the hump at 84-81 with a half-minute left in the third. And they still led 106-105 on Dinwiddie’s driving layup with 24 seconds to play. But they couldn’t hold it.

After consecutive losses, the Nets saw their lead on eighth-seeded Orlando shaved to just a half-game. And it’s their own inconsistency that’s cost them.

“That is just something that we have to look at as a team, and we have to look at ourselves in the mirror individually, and fix what we feel like we can get better at, and the coaching staff does what they do best and put us in the right position,” Taurean Prince said.