World number one Naomi Osaka bowed out of the Miami Open as the unorthodox Hsieh Su-Wei came from a set down to beat the top seed 4-6 7-6 (7-4) 6-3.
For the second time this year Osaka struggled against the world number 27 as her slices and drop shots frustrated the Japanese.
Osaka battled back against Hsieh at the Australian Open, but she could not find a way through as Hsieh completed a stunning comeback to reach the last 16.
Hsieh took the first set off Osaka in Melbourne and looked on course to do the same in Miami as she opened up a 4-1 lead, with variations keeping her rival guessing.
Buoyed by the motivational words of coach Jermaine Jenkins at the changeover, Osaka responded in emphatic style, her previous problems quickly banished.
Her piercing groundstrokes clipped the lines with unerring accuracy and in no time she had reeled off five successive games to take a one-set lead.
A break in the opening game of the second set suggested Osaka would stroll to success but when she had the chance to serve for the match she double faulted before sending a backhand wide.
In the tie-break Hsieh turned the screw and Osaka's focus seemed to drain away in the decider and her accuracy suffered, the winner of the last two grand slams noticeably flustered.
Osaka had to compose herself when Hsieh broke to move 4-3 ahead and initially it looked to have worked, but she was unable to finish the job as Hsieh completed a memorable win.