There was a lot to unpack in the Nets’ season opener, but here’s the bottom line. They were outmuscled early, and out-executed late.

And when it was over — by the time the final play broke down and saw last-ditch misses by Cam Thomas and Cam Johnson — the Nets had suffered a 114-113 loss to Cleveland before a sellout crowd of 17,931 at Barclays Center.

It was a game they’d appeared to have handed away in the first quarter, clawed back to win in the fourth, only to blow a lead late.

Up by six with 1:17 to play — and 113-111 with 13 seconds left — the Nets gave up a go-ahead 3-pointer by Cleveland star Donovan Mitchell (team-high-tying 27 points).

And their poor execution saw them fail to get the look they wanted for Mikal Bridges.

Thomas (game-high 36 points) ending up missing an off-balance 3-point attempt and Johnson’s acrobatic put-back attempt at the buzzer falling short.

Like the Nets on this night.

“Tried to get open. Thought it was a tough pass for Cam. I think it was just a tough, risky pass for him,” Bridges said.

“I was trying to call timeout,” Jacque Vaughn said. “I wish I had a buzzer that I could push [that] the referees are locked-in. The play was for Mikal. Caris [LeVert] did a great job of fighting over and making it tough. Cam was supposed to hit it to Mikal. Couldn’t call timeout. I’m across half-court trying to, though.”

It was typical of the evening for the Nets.

Despite Thomas’ early brilliance, with 24 in the first half, the Nets dug themselves a 13-point hole early at 22-9.

Still trailing 95-91 with 10:25 left to play, Brooklyn reeled off 10 unanswered points.

Backup point guard Dennis Smith Jr. — who played large chunks of the fourth quarter with starters Ben Simmons and Spencer Dinwiddie on the bench — grabbed a rebound and hit a go-ahead 3 to make it 97-95.

Johnson’s drive put the Nets up by four, and Smith made it 101-95.

Bridges — who had 11 of his 20 in the fourth quarter — hit two free throws to make it six with 1:24 remaining, but the Nets couldn’t close the deal.

Simmons finished with 10 rebounds and a game-high nine assists, but just four points.

He and Dinwiddie played roughly a minute-and-a-half each in the fourth.

Mitchell, a Westchester product whose name will be linked in trade rumors with both New York teams, came back to haunt the Nets.

“We just got to have counters. We gotta just have, on offense, if plays get denied or something, we gotta know what’s next. We gotta know what we gotta do second action, or if they’re top-blocking everything and back-cut at the big, we gotta flow. We gotta know what we’re doing. It’s the first game so we just learn from it and get ready for the next one,” said Bridges, who had five first-half points on 1-of-5 shooting.

“The physicality which they played with, every dribble handoff, they got us off our spots. They were being extremely aggressive trying to get between those dribble handoffs. Every catch that we had was pushed out,” Vaughn said. “So Mikal is gonna face that. That’s part of it, being on top of the scouting report. And the physicality that he has to combat that with, it’s a great lesson for our entire group.”

Thomas, who thrived in the midrange, didn’t seem bothered by Cleveland’s physicality.

But he had 15 in the first quarter, 24 at the break, and seemed winded at times late, part of the reason Vaughn didn’t go to him earlier in the fourth.

“If you watched that thing, he was tired after that stretch we had put him in before,” Vaughn said. “So then I went offense-defense with he and Nic [Claxton]. But the way he shook my hand coming out of the game after that stretch that we’d given him, I thought the minutes overall were where they needed to be.”

Next up is a date with former Net Kyrie Irving on Friday in Dallas, their first meeting since the star forced his way out of Brooklyn last season.