World number one Novak Djokovic suffered a shock defeat by qualifier Jiri Vesely at the Dubai Tennis Championships on Thursday, falling to a 6-4 7-6(4) loss in the quarter-finals of the ATP 500 event.

The Serbian’s defeat meant that U.S. Open champion Daniil Medvedev — who is currently competing in Acapulco — will move to the top of the world rankings next week.

Playing in his first event since being deported from Australia ahead of the year’s first Grand Slam tournament, an off-colour Djokovic lost serve in the opening game as Vesely matched him stroke for stroke.

Djokovic broke back at 1-2 but was never allowed to settle by Vesely, whose clever drop shots had his opponent scrambling at the net as the Czech sealed the first set 6-4.

The 20-times major winner started strongly in the second set but Vesely maintained his high level, racing into an early lead in the tiebreak to clinch his second career victory over Djokovic.