DOHA, Qatar (AP) Top-ranked Novak Djokovic was upset by Ivo Karlovic of Croatia 6-7 (2), 7-6 (6), 6-4 while playing through a sandstorm in the Qatar Open quarterfinals on Thursday.
Karlovic took advantage of a second break point in the seventh game of the third set with a perfect forehand pass.
He never offered Djokovic a break-point opportunity in the 2-hour, 15-minute match.
Karlovic added 21 aces to his resume for a career total of 9,062. This week, he joined Goran Ivanisevic (10,183) and Andy Roddick (9,074) as the only players to serve more than 9,000 aces in a career.
In the semifinals, he will play David Ferrer, who beat Dustin Brown of Germany 6-2, 6-2.