Novak Djokovic's bid to retain his BNP Paribas Open title came to an abrupt halt at the semi-final stage after the world No. 1 was upset by John Isner at Indian Wells.

35970 - Djokovic stopped in his tracks by Isner

Djokovic looked to be on course for a routine victory after an early break in the opening set, but he was pegged back by Isner, who took the opening set on a tiebreak.

The Serb bounced back to force a decider, but he could not find a way past an indomitable Isner, who wrapped up a 7-6(7) 3-6 7-6(5) victory in two hours and 45 minutes.

Isner, who is set to break into the top ten for the first time following his impressive run in California, won fewer points than his opponent, but held his nerve in the tiebreaks to condemn Djokovic to only his second defeat of the season.

Isner fired 20 aces past Djokovic, the last of them a 135kph serve to clinch the match and a first career win over Djokovic.

Next up for the American is the in-form Roger Federer, who defeated arch-rival Rafael Nadal in straight sets to qualify for the decider.