Maybe the absence of Draymond Green messed up their chemistry.

Or perhaps the Golden State Warriors, in the opening game of a three-game eastern swing, were caught looking past their opponent and toward their Christmas Day matchup against the Cleveland Cavaliers.

Whatever the reason, the visiting Warriors, wearing their home white uniforms, certainly didn’t look like the team with the NBA’s best record in the first half last night against the Nets at Barclays Center. They trailed by 16.

But then Kevin Durant took matters into his own hands to turn things around.

A handful of fans tried to heckle Durant with chants of “OKC,’’ “Russell Westbrook,’’ and “Westbrook’s better,’’ but 15 seconds into the second half, Durant silenced the home fans when he drove the lane and posterized Brook Lopez with an angry-looking dunk and a three-point play. That started the 24-5 run that would carry them to the lead and propel them to a 117-101 victory.

“A big play, huge play,’’ Warriors coach Steve Kerr said. “It got our guys going, got our bench going.’’

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According to Kerr, though, it was improved defense that allowed the Warriors to score the first 12 points of the second half and take charge. Durant’s play, he pointed out, was the result of a play by Steph Curry.

“Again, that was the result of a steal from Steph,’’ he said. “The overall defensive intensity the beginning of that third quarter changed things.’’

Durant finished with 26 points, nine rebounds and seven assists as the Warriors won their sixth in a row. Klay Thompson, who struggled in the first half, had 23 points for Golden State. Curry finished with 15 points and seven assists.

The Warriors had to play without Green, who returned to the Bay Area in the morning because his girlfriend had delivered the couple’s son, Draymond Green Jr., early in the day. Kerr said before the game that he shouldn’t have allowed Green to make the trip to Brooklyn in the first place.

“I’m disappointed in myself that I didn’t insist Draymond stay home yesterday,’’ Kerr said. “I tried to get him to do it and I didn’t fight hard enough, and I’m bummed that he didn’t make it back for the actual birth. But he’s home now.’’

Kerr said he spoke to Green after the Warriors’ 104-74 home victory over Utah on Tuesday night about not traveling, but Green was convinced that the baby would not arrive for at least another week.

“Typical father,’’ Kerr said. “He was wrong.’’

Without Green in their lineup (Kevon Looney, a 6-9 forward in his second year out of UCLA, started in his place), the Warriors didn’t look like themselves. They couldn’t stop Lopez (23 first-half points) and trailed by 16 points at halftime. Golden State’s best player in the first half was center Zaza Pachulia, who had 10 points and eight rebounds at intermission and shot 4-for-7 from the field.

The Warriors asserted themselves immediately once the second half started, which came as no surprise to Durant.

“We were all positive coming into the locker room. No pointing fingers, none of that stuff,’’ he said. “And we knew it was just a matter of time. [The Nets are] a young team. They’re getting better every game, but we knew at some point they’d let us back in. We didn’t know when, but we just wanted it to be early coming out of the half.’’