There’s losing a game, and then there’s playing like a losing team. 

There’s getting beat, and then there’s rolling over. 

Sunday was the latter. 

The Nets came back to Brooklyn and got humiliated on their home floor, 136-109 by the Pacers at Barclays Center. 

Or more to the point, they humiliated themselves. 

“The performance we put up after the first quarter was just unacceptable — 112 points in three quarters, you’re not winning basketball games. So it didn’t feel good on either end of the floor,” said coach Jordi Fernández. “And I’m the first one. We have to help them better. 

“[It was] just disconnection, full-on and everything: from the spacing to the plays that we run, to the communication on pick-and-rolls, to multiple efforts, to being disappointed with a mistake and dropping your shoulders. All those things are losing things, and now we did not look like a winning team out there.” 

Whether it was tired legs on the tail end of a back-to-back, the fact is the bottom fell out defensively for the Nets, who fell to 0-3 and play Tuesday in Boston. 

Yes, the offense did go missing, shooting 41 percent overall and 13-for-39 from 3-point range. Julius Randle, Michael Porter Jr. and Egor Dëmin combined for just 23 points on 7-for-27 shooting (1-for-11 from deep) to finish a combined minus-50. 

But the defense was even worse. 

The Nets allowed 57 percent shooting and 21-for-43 from 3-point range. And while the first quarter was competitive, the rest was capitulation. 

The Nets allowed 112 points on 60 percent shooting and 18-for-32 from long range over the final 36 minutes. 

“They had a little run at the end of the third or the beginning of the third, and then it felt like we just rolled over as a team. We came back from 20-some [Saturday], made it a game. I think we should stay in the fight,” said Porter, who had 10 points on 4-for-13 shooting. “Whether we hit adversity or not, as a team we’ve got to be resilient, top to bottom and just keep fighting, keep plugging away.” 

There was nowhere near enough fighting and precious little plugging away. 

Just a bunch of Indiana highlights … and Nets lowlights. 

There was Porter getting blocked at the rim by backup Jay Huff. 

And after a turnover by Randle (10 points, 2-for-8 shooting), Pascal Siakam got the ball upcourt to Tyrese Haliburton so the Pacers star could bounce it off the floor to himself for a disrespectful breakaway dunk. 

That left the Nets down 83-68 in the third with the Pacers laughing on the bench. 

Haliburton finished with 24 points and 10 assists for a plus-29. Siakam finished with 21. 

Dëmin had just three points for the Nets in 1-for-6 shooting. He was a minus-20. 

Moritz Wagner’s 3 had the Nets up 51-49 with 2:45 left in the half, but they surrendered a 16-5 run the rest of the way to go into the locker room down by nine. 

They were still down 88-74 midway through the third on Nolan Traore’s free throw, but promptly conceded a dozen straight. 

Obi Toppin’s layup capped the blitz to make it 100-74 with 3:19 left in the period. The Nets trailed by 26, and unlike the night before — when they cut a 22-point fourth-quarter deficit in Cleveland down to just two — there was no comeback. 

“The biggest [problem] is our communication. We’re just not all on the same page,” said Randle. “We’ve got to find a way to communicate better, respect communication amongst each other. If a guy calls something, we’ve got to honor the call. 

“But whatever it is, we’ve just got to communicate on that end because we do a lot of switching. So if we’re going to do a little switching, we’ve got to be communicating, and guys have got to know what the other guy’s doing. We’ve got to be on a string. We haven’t been so far.”