World number one Aryna Sabalenka moved into the Miami Open last 16 after opponent Elena-Gabriela Ruse retired injured, while there were wins for Naomi Osaka and Coco Gauff.
Sabalenka had taken the first set 6-1 before Romanian Ruse retired with a thigh problem in the first game of the second.
Japan’s Osaka survived a scare to eventually overcome American wild card Hailey Baptiste in a match lasting nearly three hours.
World number 98 Baptiste was a break up and serving at 4-3 in the decisive third set, but Osaka came back well.
The four-time Grand Slam champion held serve before breaking Baptiste again to take the match 7-6 (8-6) 3-6 6-4 in two hours, 59 minutes and 57 seconds – the longest women’s match of the tournament so far.
