Juan Martin del Potro has snapped Novak Djokovic’s winning streak to reach the finals at the BNP Paribas Open.

The 24-year-old Argentine tennis star rattled off forehand winners in key moments to defeat the world’s No. 1 player in the semifinals of the Indian Wells-based tournament on Saturday.

With the victory, del Potro handed Djokovic his first loss in 21 matches dating to last October.

del Potro snapped his own four-match skid against Djokovic, who’d beaten the Argentine in eight of 10 career meetings.

“I’m trying to hit hard with my forehands. When I have the chance to come to the net, I did all the time,” he said. “I was just focusing to put in my first serve and move to my forehands, trying to make winners.”

del Potro’s 133-mph ace closed out the nearly 3-hour match featuring nine breaks of serve in 96-degree heat. He raised both arms in celebration and Djokovic hugged him at the net.

del Potro, the second Argentine to reach the final here, will play Rafael Nadal for the title on Sunday. They each have three wins against each other on hard courts.

“When you play the top guys, they are the favorites, but I will try to do my game like just like today and then see if Rafa give me a little chance to win,” del Potro said.

Djokovic attributed del Potro’s dramatic turnaround to “his fighting spirit and my lack of concentration.”

“I didn’t deserve to win. Whenever I had chances, second, third set, I throw them away with some unforced errors. My movement was poor, and I congratulate my opponent,” he said.

del Potro had 25 winners, 34 unforced errors and saved 7 of 11 break points.