Petra Kvitova started the clay-court season by losing to countrywoman Kristyna Pliskova in the first round of the Volvo Car Open.
CHARLESTON, S.C. (AP) Kristyna Pliskova rallied from a set down to knock out two-time Wimbledon champion Petra Kvitova at the WTA's Volvo Car Open on Wednesday.
Kvitova of the Czech Republic won six of the first seven games to take the opening set before countrywoman Pliskova came back for a 1-6, 6-1, 6-3 victory to advance to the round of 16 in the WTA's first clay-court event of the season.
No. 5 seed Julia Gorges of Germany topped American Kristie Ahn 2-6, 6-4, 7-6 (1), No. 8 Anastasija Sevastova of Latvia defeated Caroline Dolehide of the United States in three sets, 7-5, 6-7 (5), 6-1, No. 9 seed Australian Ashleigh Barty ousted Tatjana Maria 4-6, 6-3, 6-2 and No. 10 seed Naomi Osaka of Japan defeated Laura Siegemund of Germany 6-3, 7-6 (8).
Other seeded winners were No. 12 Kiki Bertens of the Netherlands, No. 13 Irina-Camelia Begu of Romania and No. 14 Alize Cornet of France.
No. 11 seed Daria Gavrilova of Australia lost in three sets to Italy's Camila Giorgi.
No. 6 seed Johanna Konta of Australia and No. 7 seed Madison Keys play later.