John Isner celebrates the biggest victory of his career after dumping out Novak Djokovic.

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John Isner shocks top seed Novak Djokovic in the Indian Wells semifinals

Isner is guaranteed a place in the world's top 10 after his three-set victory

Roger Federer also through to the final after straight sets win over Rafael Nadal

CNN  — 

American John Isner has claimed the biggest victory of his career with a battling three-set win over world number one Novak Djokovic in the semifinals of the Indian Wells tournament.

World number 11 Isner fired 20 aces, including one on match point, to progress 7-6 (9-7) 3-6 7-6 (7-5) after two hours and 45 minutes and seal a place in the final against Roger Federer.

Third seed Federer defeated rival and world number two Rafael Nadal 6-3 6-4, also sealing the match with an ace.

Isner, who is now guaranteed a place in the world’s top 10, was understandably delighted after beating a world No.1 for the first time in his career.

He told the official ATP Tour website: “That’s why I play this game, to be able to enjoy moments like that.

“The stadium was packed and there wasn’t a spare seat in the house. It was very special when that last ball went by him and I knew I had won the match. “

The 26-year-old Isner is aiming to win his fourth ATP Tour singles title, but his first since claiming the Winston-Salem Open last August.

“Not many people can say they’ve ever beaten the No. 1 player in the world. I will always be able to say that and I’m just going to keep on riding this wave and see how far it can take me.”

Defeat for 24-year-old Djokovic marked the second time this month that the Serb has lost at the semifinal stage, following his reverse to Andy Murray in Dubai.

Djokovic told the ATP Tour website: “I had 30-all a couple of times in the final set, but he came up with some incredible winners.

“I just had to shake his hand and congratulate him for the win,” added Djokovic.

Meanwhile, the latest installment of the Federer/Nadal rivalry went the Swiss maestro’s way, who proved victorious after one hour and 31 minutes of a match interrupted by rain delays.

The pair had met 27 times previously, and Nadal still leads the way with 18 wins. But they had never met before at Indian Wells, and it was Federer who coped better with the court and conditions.

“It was a great match in tough conditions but I couldn’t be more happy. I played amazing,” Federer told reporters.