The new-look Nets are starting to figure out how to play together. But they fell to a team that already knows how to win together.

Rebuilding Brooklyn looked good in stretches, but the white-hot Bucks were great when it counted. The Nets took a big lead but couldn’t hold onto it, losing 118-104 to Giannis Antetokounmpo & Co. before a sell-out crowd of 17,732 at Barclays Center.

“This is one of the top teams in the league,” Jacque Vaughn had warned beforehand. “Great test for us to see where we’re at mentally and physically. Trying to jell together on both ends of the floor. Saw some progress [in Sunday’s loss] versus Atlanta so can we continue to grow. They offer the challenge of continuity so they’ve been around each other.”

The Bucks aren’t one of the best — they are the best, now a league-leading 44-17 after reeling off a 15th consecutive victory.

Brooklyn built a 15-point cushion, and it was still double figures almost midway through the third quarter.

But Antetokounmpo had seven points and several highlight plays in a 27-9 blitz that spanned the third and fourth quarters, and sunk the hosts.

Antetokounmpo finished with game highs of 33 points and 15 rebounds, physically dominating Brooklyn the way he does just about every team he plays.

And his 12-foot fadeaway capped the run, and put the Nets in a 93-85 hole just 30 seconds into the fourth quarter.

Brooklyn fell to 1-5 since trading away Kevin Durant, despite the best efforts of Mikal Bridges.

He’s the centerpiece of the Durant return, a young standout Milwaukee coach Mike Budenholzer recalls well from the Bucks’ NBA Finals matchup against the Suns.

“He just feels like he’s getting better and better,” Budenholzer said. “I don’t know if that was his third or fourth year in the league, to play at that level in the NBA Finals and be a guy that defensively and offensively, the coach trusts him, his teammates trust him, and now he’s in a new situation.

“He’s getting the ball more. I just think his ballhandling, his slashing, getting to the basket, pull-up game, his understanding of timing and angles. He’s a good player now, and it feels like he’s getting more of an opportunity.”

Bridges had a team-high 31 points, including 11 quick points to spot the Nets to an early 28-13 lead.

Spencer Dinwiddie — who added 26 points — hit a pull-up 3 to make it 28-13 with 3:06 left in the first quarter.

But the Bucks played that half cruising in third gear, while the Nets were going full throttle.

Milwaukee’s starters played just 68 total minutes in a relaxed first half, while Brooklyn’s logged a hefty 93.

It was completely understandable, a clear indicator of how much Vaughn wanted to win this one.

With Brooklyn up 62-52 at the break, the Bucks stormed out of the locker room with a 12-2 run, Brook Lopez tying it at 64-all with a 3-pointer.

It was still 66-all when Brooklyn ripped off 10 unanswered points, a Bridges 18-foot pull-up making it 76-66 with 6:47 in the period.

But the Bucks reeled off the 27-9 run to put it away.

Brooklyn shot just 3 of 13 in an ice-cold drought that cost it. Meanwhile, the Nets saw Milwaukee hit 12 of 16 — including 7 of 8 in the paint and 4 of 4 at the rim.

The Nets ran out of gas down the stretch.