Former world number one Caroline Wozniacki was knocked out in the second round of the Nottingham Open with a 6-7 6-3 7-5 defeat by Anett Kontaveit.
Third seed Wozniacki, 25, has fallen to 34th in the world rankings and missed the recent French Open through injury.
Top seed Karolina Pliskova, 24, earlier advanced to the quarter-finals with a 6-1 6-3 win over Anna Tatashvili.
British number one Johanna Konta and compatriot Tara Moore play their second-round ties on Thursday.
Konta, 25, faces China's Zheng Saisai, who she beat in the second round of the Australian Open in January.
Moore, 23, will take on American eighth seed Christina McHale as she attempts to reach the third round of a WTA event for the first time in her career.
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