Mikal Bridges and Spencer Dinwiddie of the Nets react late during...

Mikal Bridges and Spencer Dinwiddie of the Nets react late during the fourth quarter against the 76ers at Barclays Center on Saturday. Credit: Jim McIsaac

The process of subtracting and adding was over now in a tumultuous week that marked the end of an unforgettable era of Nets basketball, and not in a good way. A new era tipped off in earnest Saturday night at Barclays Center.

Mikal Bridges and Cam Johnson, who came to Brooklyn from Phoenix on Thursday in a large package for Kevin Durant, made their Nets debuts against Philadelphia. They joined Spencer Dinwiddie and Dorian Finney-Smith, who both played in Thursday night’s home win over Chicago after being traded from Dallas in the Kyrie Irving deal.

Nets coach Jacque Vaughn has been left to weave the new guys into the fabric of this team with the holdovers amid a continued run at the playoffs. He decided to start all four newcomers alongside Nic Claxton against the 76ers.

Bridges stood out with 23 points, but after leading most of the way, the Nets fell behind late by three points, only to see Dinwiddie nail a three-pointer at the buzzer. Overtime? No, after a video review it was determined the shot came too late. Philadelphia emerged with a 101-98 victory.

“Just stinks,” Bridges said. “But we played good. For the first time for all of us to play, I think we defended really well.”

Except against Joel Embiid and James Harden.

Embiid capped a 37-point, 13-rebound night by hitting the tying and go-ahead free throws with 5.2 seconds left to put the 76ers ahead 99-98.

On the ensuing possession, Bridges drove to the basket but missed a layup and the Nets had to foul Harden. He capped a 29-point night by hitting two more free throws with nine-tenths of a second left for the three-point margin.

The Nets fell to 33-23 and are in fifth place in the Eastern Conference — three games ahead of the seventh-place Knicks, whom they will play on Monday night at Madison Square Garden.

“It’s the beginning chapter of a new era,” said Vaughn, who didn’t get the win he wanted on his 48th birthday. “This group gets to tell their own story. That’s what we’re going to allow them to do, come together, figure things out, find a way to get this thing done.

“But the expectations remain the same. What that looks like at the end, I don’t know what the last chapter of the book looks like.”

This first page of the first chapter didn’t end well.

The Nets called their last timeout to set up a play after Harden made it 101-98. Dinwiddie was left open on the inbounds pass and drilled a three-pointer from 32 feet, straightaway. But the video review showed the ball was still on his fingertips at the buzzer, and the game was over.

“Obviously, I just tried to do my best job of just catch and shoot the ball,” Dinwiddie said.

After the 76ers (36-19) cut an 11-point third-quarter deficit to three early in the fourth, the Nets responded. Joe Harris (18 points on six three-pointers) hit a pair of threes in an 8-2 run that put the Nets ahead 90-81.

Philadelphia kept coming. Embiid nailed a 14-footer, and the Nets’ advantage was down to 96-95. Then Dinwiddie burst down the lane for a slam to give the Nets a three-point edge with 1:45 left.

Those were the only points the Nets scored inside the final 6:52. The 76ers closed with a 14-2 run.

“We were getting good looks,” Bridges said.

Embiid scored from six feet to cut the deficit to 98-97 and sent them ahead with his free throws. He was 12-for-13 as Philadelphia went 29-for-30 from the free-throw line; the Nets were 11-for-13.

Dinwiddie pointed to that disparity but added, “I think overall the energy of the group is high and the optimism is high.”

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