The former Georgia player will take on either No. 2 Rafael Nadal or No. 3 Roger Federer in today’s final, with Isner trying to become the first American winner in the desert since Andre Agassi in 2001.
Nadal and Federer were to play for the 28th time but the first at Indian Wells in the other semifinal, although rain began falling shortly after Isner left the court on a cool, cloudy day.
Victoria Azarenka and Maria Sharapova will meet for the women’s title today.
Isner’s victory guaranteed he will break into the top 10 for the first time in next week’s ATP Tour rankings at No. 10. A victory in the final would move the American to No. 8, passing countryman Mardy Fish who is now No. 8.
Isner is the first American to beat a world No. 1 since James Blake defeated Federer in the 2008 Beijing Olympics.
Isner needed nearly three hours to reach his first ATP Masters 1000 series final after 25 tries.
He didn’t get past the round of 16 in his first 23 events until making his first semifinal in Paris last fall and now the final in the desert.
The 6-foot-9 American towered 7 inches over Djokovic, giving Isner an easy advantage with his serve-and-volley game. He played a few loose points in the 12th game of the final set, sending a forehand past the baseline on his first match point, and Djokovic held to force the second tiebreaker.
Isner aced Djokovic with a 143-mph serve to lead 3-2, then hit a forehand winner down the line to go up 4-2.
“I told myself I was going to run around the backhand and hit a forehand, and I was just hoping that he wasn’t going to hit the serve up the T. He had been doing that quite a bit, especially on the ad side,” Isner said. “I wanted to put a good hit on the ball because if you don’t, he just gets you moving. That’s why he’s the best in the world.”
Isner’s 144-mph serve forced Djokovic into a netted return that set up Isner’s second match point.
Even Djokovic caught himself looking at the scoreboard to see how fast Isner’s serves were.
“Sometimes just to admire, because I will never get there,” the Serb said, laughing.