There were no changes in the top 10 of the latest WTA rankings published on Monday, while Petra Kvitova of the Czech Republic slipped two places to 13th.

Kvitova lost to Romania's Monica Niculescu in the final in Luxembourg, with the winner climbing 14 places to 37th as a consequence.        

WTA top 10

1. Angelique Kerber (GER) 8,000 points; 2. Serena Williams (USA) 7,050; 3. Agnieszka Radwanska (POL) 4,975; 4. Simona Halep (ROU) 4,728; 5. Karolina Pliskova (CZE) 4,100; 6. Garbine Muguruza (ESP) 3,736; 7. Madison Keys (USA) 3,637; 8. Dominika Cibulkova (SVK) 3,625; 9. Svetlana Kuznetsova (RUS) 3,490; 10. Johanna Konta (GBR) 3,455