PORTLAND, Ore. — The Nets had the worst defensive performance in their history Tuesday night against the Kings in Sacramento. They bounced back with a huge victory Thursday night against the Trail Blazers.

Kevin Durant had a monster night, but it was Royce O’Neale’s tip-in of Durant’s missed fadeaway with a fraction of a second left that gave the Nets a 109-107 victory before a sellout crowd of 19,393 at Moda Center.

Coming on the heels of their desultory 153-121 loss to the Kings, this was the Nets’ most important win of the season, a gut-check of a win over the Western Conference leaders.

“Without a doubt [this was huge]. We didn’t do everything perfect at the end of the game, and so for us to still stay together, didn’t panic and come through on the other side — that’s huge. A group grows that way,” coach Jacque Vaughn said after the win.

“I’m still excited. … If a coach could draw up a game and ended up winning at the end, that was it.”

Durant scored a game-high 35 points and O’Neale had a triple double with 11 points, 11 assists and 11 boards — none more important than his final offensive rebound, a put-back of Durant’s miss with 0.7 seconds left.

“We had a great film session right before we left Sac,” Durant said. “We were able to come out and play our brand of basketball, which is gritty defensive basketball. Get up and down the floor. We hit all those points.”

Yuta Watanabe finished with 20 points and seven rebounds, while Ben Simmons had his best effort of the season with 15 points, 12 boards and seven assists.

Durant became just the 19th player in league history to reach 26,000 points. He has 25 points in each of the Nets’ first 16 games, the longest such run since Michael Jordan in 1988-89.

Damian Lillard led the Trail Blazers with 25 points and 11 assists, while Anfernee Simons added 24 points.

The Nets led 85-82 going into the fourth quarter before the Blazers went on a 9-2 run. But with Portland still up, 95-90, the Nets ripped off 10 unanswered points., including a key challenge by Vaughn to overturn a foul on Seth Curry.

Simmons, intentionally fouled with 3:28 left, made one of two. The Blazers fouled him again 32 seconds later, and Simmons hit both for a 103-99 lead.

“For me, I love those moments. I’m not going to shy away. That was their plan. Obviously, it didn’t work,” Simmons said. “It’s building. I like those moments.”

Watanabe’s corner 3-pointer made it 106-101 with 1:47 left.

An ill-advised offensive foul by Durant away from the ball gave Portland the ball with the Nets clinging to a 106-103 edge. Simmons then fouled out, sending Jusuf Nurkic to the line, but he only made one of two, leaving the Nets up by a deuce.

Durant went to the line with 14.9 seconds left. He missed the first free throw, but made the second.

Just as missed free throws by Durant had hurt in a Nov. 7 loss at Dallas, that miss seemed set to haunt the Nets when Nurkic completed a three-point play with six seconds left to knot the score.

Until O’Neale untied it, that is.

“Big time. Especially just bouncing back from the Sacramento loss and the way we played,” O’Neale said. “We knew we had to come out with a sense of urgency.”