SAN FRANCISCO — This Western swing was always going to be a tough trip for the Nets.

Saturday’s slow start and 124-120 defeat at Golden State ensured it would be a losing one.

The Nets can look in the mirror for this one.

They dug themselves into a huge hole early, and when they tried to climb out late, Stephen Curry made sure they couldn’t.

Mikal Bridges missed a potential game-tying layup with 24 seconds remaining, and Curry sealed it with a layup on the other end.

“I just missed it,” Bridges said. “Just missed the layup. Coach drew the play up for me to get iso up top. And I just missed the layup.”

Curry finished with 37 points, including a dozen Warriors points in a row during the pivotal fourth quarter after the Nets had turned an 18-point deficit into a 103-102 lead.

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Golden State Warriors guard Stephen Curry (30) gestures after making a 3-point basket.AP
Brooklyn (13-11) also squandered a brilliant 41-point outing from Cam Thomas.

“[They] closed it out because they’ve got Steph Curry. He controlled the game, started making shots at the end, and that’s why he is who he is. So he really just took the game over,” said Thomas, who broke out of his recent funk to hit 15 of 24.

But Curry hit the shots that mattered most in clutch time, and — with the Nets without top defenders Dorian Finney-Smith and Dennis Smith Jr. — they couldn’t slow him.

“At the end day he’s still Steph Curry, no matter who’s guarding him,” Thomas said. “He’s one of the greatest ever. He just took the game over, there’s really nothing to it. Obviously those guys would’ve helped. But he was locked in. He was 6-of-8 from 3. There’s nothing you can do with that, honestly. So obviously those guys would’ve helped, but it’s tough. He took the game over. There’s nothing you can do about it.”

Well, not falling into an 18-point hole in the third quarter would’ve helped.

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Brooklyn Nets guard Cam Thomas, right, drives to the basket against Golden State Warriors forward Dario Saric.AP
Then it wouldn’t have come down to Curry’s late daggers or Bridges’ miss.

“We didn’t come up with that in the first half, came a little sluggish, a little slow.

Some bad turnovers, turned the ball over a lot,” Thomas said.

“I can just look myself in the mirror and do that,” Nic Claxton said. “From the jump I just wasn’t as aggressive as I needed to be, especially on the defensive side of the ball. And when you’re on the road especially, and you’ve got a lot of different things going against you, you’ve really got to be locked down from the jump.”

Golden State had played a league-high 20 “clutch games” — contests within five points in the final five minutes of regulation or overtime.

And they know how to pull out games this one.

Curry cracked the 3,500 mark for career 3-pointers and hit from downtown in a 268th straight regular season game — both NBA records.

And he made the killer daggers from deep in the final stages.

Leading 17-16 on a Cam Johnson drive, the Nets surrendered a quick 6-0 mini-run to fall behind by five when Chris Paul found Dario Saric for a 3-pointer.

The deficit was seven when the Nets gave up an 11-0 two-minute blitz.

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Golden State Warriors guard Stephen Curry talks with Brooklyn Nets guard Cam Thomas.AP
Down just 55-48 after a Nic Claxton layup, the Nets missed four straight shots and committed a couple of turnovers, quickly losing contact.

The deficit bloated to 66-48 on a Jonathan Kuminga putback with 2:21 left in the first half.

It was still an 18-point deficit early in the third, before Brooklyn slowly and inexorably shaved that hole in half with less than a minute remaining in the quarter.

Royce O’Neale and Thomas sandwiched 3-pointers around a Paul miss to get the Nets within 92-89 with a half-minute left in the third.

And after a quiet start to the night — three points at halftime on 1-for-6 shooting — Bridges drilled a left-corner 3-pointer to finally put the Nets ahead 99-97 with 9:12 to play.

But with the score knotted at 106-all, Curry untied it.

He hit from 27 feet, then — after Brandin Podziemski stole a bad Bridges pass — a 30-footer that sent the Nets scurrying into a timeout.

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Brooklyn Nets guard Spencer Dinwiddie shoots in front of Golden State Warriors guard Stephen Curry.AP
It didn’t help.

Thomas lost the ball — another Podziemski theft — and Curry’s midrange jumper left Brooklyn down 114-106 with 4:34 in regulation.

O’Neale pulled Brooklyn within 120-118 with two minutes left, but no closer.

Bridges missed a layup with 24 seconds left, and Curry sealed it with a layup on the other end to ensure there would be no overtime.

“I take a lot of accountability,” Claxton said. “The scout was for me to be up and put pressure on the ball up on [dribble handoffs] and everything, and I wasn’t as aggressive as I should’ve been from the jump.

“And I’m the catalyst for the defense so I definitely take accountability for that.”