Nets get harsh lesson from Jayson Tatum, Jaylen Brown in blowout loss to Celtics

The Nets didn’t just lose a game. They lost their fight.

Brooklyn rolled over for the first time under new coach Jordi Fernandez, a 139-114 capitulation against the Celtics before a sellout crowd of 18,112 at Barclays Center.

And Fernandez wasn’t making any excuses for their effort, because it was inexcusable.

“I’m OK with losing, but I’m not okay with, at one point in the game, not fighting,” Fernandez said. “You can never, ever, ever, quit or look defeated, whatever the case may be. We have to continue to do things the right way, and if one night the other team is better than you, then you gotta respect it. But this — flashes of not doing the right things — this is not what we want to be at all.

“And we haven’t done it. It’s just easier against adversity. Whatever you want to call ‘adversity,’ to me, it’s all excuses. The NBA, it is what it is. Everybody deals with stuff and you don’t want to be like, finding the excuse. We have more than enough to be better than this. To me, that’s plain and simple.”

After blowing a fourth-quarter lead last Friday in TD Garden — falling in overtime to the Jaylen Brown-less Celtics — Wednesday was no heartbreaker. It was more of a reminder the Nets have to play hard, and what happens when they don’t.

Jayson Tatum had a game-high 36 points and 10 ᴀssists, and Brown added 24 points and 12 rebounds.

The Nets failed to fight through screens and saw their league-leading 3-point defense shredded.

“The things that we can control, we weren’t controlling tonight. That’s why we got whooped, man,” said Ziaire Williams, who had a team-high 23 points starting for injured Dorian Finney-Smith. And he backed up Fernandez’s critique.

“I agree, man. We just let them, you know, stomp on our necks. They definitely had more fight. … They just wanted it more than us, man.”

The Nets had allowed the fewest 3-pointers in the NBA, running foes off the line.

They harᴀssed the Celtics into missing 39 3-point attempts last Friday, but on Wednesday, they got torched for 22 of 45 from deep.

“Yeah. It’s something we can control. Just focusing on a game plan, everything that the coaches ask for us. We just fell off in the second half. We didn’t do it for the whole game,” Nic Claxton said.

Asked about Fernandez’s postgame message, Claxton replied “S–t. He just pretty much stood on business. We need to play hard. That’s not the way you lose. Of course, you never want to lose games. But that’s not the way that you lose. We didn’t fight all the way through.”

Cam Thomas had 17 for the Nets, who got outmuscled.

Williams spotted the Nets to an early 19-8 lead with a layup.

Cam Johnson’s 3-pointer padded the cushion to 26-13.

It was still 58-55 after Dennis Schroder (16 points) made a free throw with 3:21 left in the half.

But the Nets allowed eight unanswered to give up the lead, and never recovered.

Payton Pritchard (23 points, eight ᴀssists, six rebounds) hit a 3-pointer to leave the Nets trailing 63-56 with 1:45 remaining in the first half.

The Nets were still trailing by four before another 8-0 run essentially ended it.

Schroder had found Williams for another 3-pointer to make it 72-68 with 9:18 left in the third, but eight unanswered Celtic points over the next two minutes took the life out of the Nets.