Emma Raducanu suffered a heavy defeat in just 52 minutes to Amanda Anisimova in the third round at Indian Wells.
The British number one was well below par in a 6-1 6-1 loss to American world number six Anisimova.
Raducanu, seeded 25, may have been struggling with a fitness issue as she repeatedly refused to chase down drop shots.
“I think I can be very pleased with my performance today,” Anisimova said in her on-court interview.
“I had a tough first round so just went out to be fearless. I wanted to enjoy it and wanted to keep the run going.”
Top seed Aryna Sabalenka eased into the last 16 with a 6-4 6-1 win over Romania’s Jaqueline Cristian.
She will meet Naomi Osaka, who needed all three sets to get past Camila Osorio of Colombia 6-1 3-6 6-1, while fourth seed Coco Gauff retired due to injury when trailing Alex Eala 2-6 0-2.
In the men’s draw, second seed Jannik Sinner needed just 71 minutes to book his place in the last 16 with a 6-3 6-2 win over Canada’s Denis Shapovalov.
Fourth seed Alexander Zverev was made to work harder before beating Brandon Nakashima 7-6 5-7 6-4 in just over two and a half hours.
