World number one Simona Halep was knocked out in the third round of the Miami Open by Agnieszka Radwanska.
Romania's Halep, 26, lost 3-6 6-2 6-3 as the 32nd-ranked Pole came from behind to win in one hour 44 minutes.
Halep had fought back from a set down to defeat France's Oceane Dodin in the previous round.
"I'm so happy, especially because she's been playing great tennis in the last couple of months," said Radwanska, 29.
"The atmosphere was great here and all worked perfectly
"Every match is special here on that court with a full stadium. You cannot ask for more."
Former world number one Karolina Pliskova needed three tough sets to battle past Hsieh Su-Wei 6-4 1-6 7-6 (7-4) and reach the last 16.
It was the first time Pliskova has faced Hsieh, who knocked out Garbine Muguruza on her way to reaching the last 16 at the Australian Open.
Wimbledon champion Muguruza, the third seed, beat America's Christina McHale 6-2 6-1 in an hour and 10 minutes.
Three-time winner Victoria Azarenka moved into the fourth round with a 3-6 6-4 6-1 win over 20th seed Anastasija Sevastova of Latvia.
American Sloane Stephens, the 13th seed, went through after Romania's Monica Niculescu retired with a back injury when trailing 4-0 in the deciding set.