INDIAN WELLS (California), March 17: Hard-serving John Isner pulled off the biggest upset of his career at the BNP Paribas Open on Saturday before Roger Federer imperiously outplayed long-time rival Rafa Nadal in the other semi-final.

Big-serving American Isner overpowered world number one Novak Djokovic 7-6, 3-6, 7-6 and will face three-times champion Federer in Sunday’s final, the Swiss having eased past Spaniard Nadal 6-3, 6-4.

Federer handled the cold, windy conditions better than Nadal, whose grumpy expression matched his out-of-sorts body language.

The second semi-final was delayed by three-and-a-half hours because of steady rain before Federer and Nadal came out for their heavily anticipated showdown, the Swiss dominating before sealing victory in one hour, 31 minutes.

Serving for the match at 5-4 and 40-30 on a chilly and blustery evening, Federer was briefly held up by a light sprinkling of rain before he powered down a 125 mph ace, his sixth in all, to book his place in the final.

“I just had a good day,” 16-times grand slam champion Federer said in a courtside interview after winning 38 of his 40 matches since last year’s US Open. “Another great match in tough conditions.

“We both expected rain in the match and it did rain a few times. I couldn’t be more happy. I have played amazing against Rafa. He is a great champion.”

Earlier, Isner blasted a total of 20 aces past the top-seeded Serb, the last of them a well-placed 135 mph serve to clinch the final-set tiebreak 7-5 and end his match after two hours, 45 minutes.

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,” he said, laughing.

Isner, who had lost to Djokovic in their previous two meetings, threw his arms skywards in celebration before light drizzle began to fall on the showpiece stadium court at the Indian Wells Tennis Garden.

“That’s why I play this game, is to be able to enjoy moments like that,” 11th seed Isner told reporters with a broad grin after reaching the final in an elite ATP Masters 1000 event for the first time.

Isner will try to become the first American winner in the desert since Andre Agassi in 2001.

Results: Men’s semi-final (prefix denotes seeding): 3-Roger Federer (Switzerland) beat 2-Rafa Nadal (Spain) 6-3, 6-4; 11-John Isner (US) beat 1-Novak Djokovic (Serbia) 7-6(7), 3-6, 7-6(5).—Reuters