Madrid Open 2019: Naomi Osaka could lose world No 1 ranking after shock defeat to Belinda Bencic

Reaching the last four would have secured Osaka's grasp on top spot for another week but her 3-6 6-2 7-5 loss to resurgent Swiss Bencic means Simona Halep can overtake her by winning the title

Osaka could lose her number one ranking (Getty Images)

Naomi Osaka could lose the world number one ranking after defeat by Belinda Bencic in the quarter-finals of the Madrid Open.

Reaching the last four would have secured Osaka's grasp on top spot for another week but her 3-6 6-2 7-5 loss to resurgent Swiss Bencic means Simona Halep can overtake her by winning the title.

Japan's Osaka has limited experience on clay but looked poised for a fine win when she served for the match at 5-4 in the decider only for Bencic to reel off three games in a row and book a clash with Halep.

The Romanian advanced via a 7-5 7-5 victory over Australia's Ashleigh Barty.

Defending champion Petra Kvitova also crashed out, the three-time winner being beaten 6-2 6-3 by Kiki Bertens in a rematch of last year's final.

Her semi-final opponent is Sloane Stephens, who defeated Petra Martic 6-4 6-3.

PA