The Nets ran their losing skid to five straight, their longest of the season.

And this defeat was also likely their worst of the season.

Brooklyn blew a game it not only needed but had wrapped up, falling 116-114 to the Cavaliers before a stunned sellout crowd of 17,732 at Barclays Center.

They led 112-104 with under two minutes left, but coughed up a 12-2 run to close the game, coming unraveled at the worst possible time.

The Nets (39-34) are now 1 ½ games behind the fifth-placed Knicks, who fell to the Magic.

They also fell half game behind the fast-charging Heat, whom they play Saturday in Miami.

They had turned a nine-point deficit into a ten-point fourth-quarter lead, only to watch Cleveland claw back within a deuce with under a minute left.

But it was fittingly Spencer Dinwiddie – who had a stellar night on both ends of the floor – that gave them breathing room with a layup that made it 114-12 with :29 left in regulation.

But after a Donovan Mitchell (31 points) step back halved the lead, Dorian Finney-Smith turn the ball over to ex-Net Caris LeVert with :13.3.

Mitchell got fouled and went to the line. He made just one of two, but the Nets failed to protect the defensive glass.

Mitchell got his own rebound, and after a mad scramble Issac Okoro drilled a left-corner 3-pointer that proved the winner.

Mikal Bridges (game high 32 points) missed a halfcourt heave.

The nets were trying to halt a slide, one that threatened to dump them headlong all the way down into the dreaded play-in.

On March 13th they were in fifth place, having won five of six and ahead of not only the Knicks but enjoying a three-game cushion on Miami.

But they haven’t had much joy since then.

After having lost Tuesday to this same Cleveland team, the Nets came into Thursday’s rematch having dropped four in a row, fallen behind their cross-river rivals and seen their lead on the Heat shrivel to just a single percentage point.

Now it is gone altogether.

Spencer Dinwiddie ended with 25 points and 12 assists.