Naomi Osaka, top seed of the women's singles, also suffered an unexpected defeat, falling to Switzerland's Belinda Bencic 6-3, 6-1 in the fourth round.

It is the second loss of the Japanese world number one after she lifted the Australian Open trophy and the 11th consecutive win for 22-year-old Bencic, who came to Indian Wells with a Dubai Tennis Championships title.

"I really wasn't focusing so much on her. I was focusing on my game. I'm very confident with my game right now. I'm hitting the ball well. So just things worked out for me," Bencic said. "I played I think a great match. I'm really happy with myself."

Second seed Simona Halep joined the top seeds crashing out after losing 6-2, 3-6, 6-2 to unseeded Marketa Vondrousova of the Czech Republic in one hour and 40 minutes. China's Wang Qiang failed to make it into the quarterfinals at the hands of Canada's Bianaca Andreescu 7-5, 6-2.

Rafael Nadal and Roger Federer survived the surprising day with easy victories over Diego Schwartzman and Stan Warinka whereas Kei Nishikori and Marin Cilic fell in the third round.