Angelique Kerber must overcome Carla Suarez Navarro in the Western & Southern Open quarter-finals to progress her bid to reach the top of the WTA rankings.
The German will replace Serena Williams - absent from this tournament due to a shoulder injury - as world number one if she wins the Cincinnati title and on Thursday she reached the last eight with a 7-6 (7/5) 6-4 victory over Barbora Strycova.
Her next opponent will be Spain's Suarez Navarro, who beat Roberta Vinci 6-1 7-5, while fourth seed Garbine Muguruza must tackle qualifier Timea Babos.
Muguruza - the reigning French Open champion and a former Wimbledon finalist - defeated Anastasia Pavlyuchenkova 7-5 6-1 at the Lindner Family Tennis Center, with Babos shocking Dominika Cibulkova by recovering to triumph 4-6 6-3 6-1.
Britain's Johanna Konta started brightly against Agnieszka Radwanska but surrendered her grip on the match to lose 6-7 (1/7) 6-4 6-0. Radwanska next meets third seed Simona Halep following the Romanian's comfortable 6-1 6-2 victory over Daria Gavrilova.
The remaining quarter-final will see Karolina Pliskova face Svetlana Kuznetsova after their respective wins over Misaki Doi and Timea Bacsinszky.
Source: PA
