Paris - Czech second seed Karolina Pliskova advanced to the fourth round at Roland Garros on Sunday with a 7-5, 6-1 victory over Germany's Carina Witthoeft.
Pliskova, who had won just twice in five previous French Open appearances before this year, will face Paraguay's Veronica Cepede Royg for a quarter-final spot.
Pliskova can replace Angelique Kerber as world number one by reaching the final in Paris.
French Open results on Sunday, the eighth day of the 2017 tournament at Roland Garros (x denotes seeding):
Kei Nishikori (JPN x8) bt Hyeon Chung (KOR) 7-5, 6-4, 6-7 (4/7), 0-6, 6-4
Caroline Wozniacki (DEN x11) bt Svetlana Kuznetsova (RUS x8) 6-1, 4-6, 6-2
Elina Svitolina (UKR x5) bt Magda Linette (POL) 6-4, 7-5
Petra Martic (CRO) bt Anastasija Sevastova (LAT x17) 6-1, 6-1
Karolna Plskov (CZE x2) bt Carina Witthoeft (GER) 7-5, 6-1