Steve Kerr has seen Kevin Durant at his best, when they spent three years and won two NBA championships together with the Warriors from 2016-19.

Kerr and the undermanned Warriors received a front-row look Wednesday night at how dominant Durant has been this season and how hot the Nets have been over the past few weeks. Durant led a balanced attack with 23 points against his former team in a 143-113 rout at Barclays Center, as the rolling Nets won their seventh in a row and 11th in 12 games.

“I think we used the word professionalism and being mature to play the game tonight, and I think that was the first piece of it,” Nets coach Jacque Vaughn said. “Our approach was pretty good, especially the first quarter after [slow starts in] the last two games.”

Royce O’Neale nailed four 3-pointers and finished with 14 points as the Nets tied a franchise record with nine players scoring in double figures for the Nets, despite the absence of starting point guard Kyrie Irving, who sat with right-calf tightness.

“That’s what basketball is to me,” said Ben Simmons, who had eight of the Nets’ 42 assists. “Guys sharing the ball, us getting the best shot we can every time down and then trusting each other.”

Durant netted 21 of his points in the first half on 8-for-9 shooting as the Nets (20-12) established franchise records for points in a quarter, with 46 in the first, and in a half, as they led 91-51 at the break. That output represented the third-most points in any half in NBA history, behind the Suns with 107 in 1990 and the Warriors with 92 in 2018.

“Well, it just looks like they’ve gotten healthy,” Kerr said of the Nets. “They’ve obviously got a lot of talent. Their guys are cooking and playing well together. They’re in a good groove.”

James Wiseman scored 30 points to lead the Warriors, who were without stars Stephen Curry, Andrew Wiggins and Klay Thompson, among others. The defending NBA champions lost for the seventh time in their last nine games to slip to 15-18, one night after being blown out by the Knicks.

“It’s the Warriors, you always respect them no matter who’s on the floor. They have a championship system and championship players,” Durant said. “Even with those guys out, they have a next-up mentality to come out and play, so you can’t take them lightly. I think we did a good job of staying focused from the start.”

Durant ruptured his Achilles tendon during the 2019 NBA Finals with Golden State and missed the entire 2019-20 season after he signed a free-agent deal with the Nets. But Kerr said he believes the superstar has regained his premier level, especially this season, when Durant has a scoring average of 30.1 points per game and a career-best .564 field-goal percentage.

“Well, he’s been one of the best players in the league for a decade. Maybe more. So he’s just one of the great scorers of all time. He’s a phenomenal shooter, he can get any shot he wants. He’s the same guy. So he doesn’t look any different to me now than he did a few years ago when he was playing with us,” Kerr said. “I’m happy for him, happy that he’s healthy and playing well. I’m happy for their team.”

Kerr, who won five NBA championships as a player alongside Michael Jordan with the Bulls and four more as coach of the Warriors, said he believes Durant and other legendary players should be appreciated while they’re still active. Vaughn said something similar about Durant this week.

Even without Irving, the Nets managed their most points in any quarter this season, with a 46-17 runaway lead to end the first session. They shot a scintillating 73.9 percent from the floor (17-for-23) and 77.8 percent (7-for-9) from 3-point range in the quarter

O’Neale sank three early 3-pointers and had 11 first-quarter points, and Durant contributed 10 as the Nets built a 29-point cushion, 46-17, through 12 minutes.

The second unit pushed the lead to 37 midway through the second quarter, and Durant buried a late 3-pointer as the Nets cruised comfortably into intermission with their 91-51 lead.