Paris – Romania's Simona Halep is up to fourth place in the world rankings despite having to withdraw from the last 16 of the Italian Masters in Rome due to injury.
Halep has edged ahead of former top ranker Victoria Azarenka, who has been sidelined since March with a foot injury.
Ahead of the French Open, which gets underway in Paris on Sunday, Serena Williams maintains a huge lead on points over China's Li Na, with Maria Sharapova down a place to eighth.
WTA world rankings:
1. Serena Williams (USA) 11,590 pts
2. Li Na (CHN) 7,540
3. Agnieszka Radwanska (POL) 6,360
4. Simona Halep (ROM) 5,140 (+1)
5. Victoria Azarenka (BLR) 4,741 (-1)
6. Petra Kvitova (CZE) 4,600
7. Jelena Jankovic (SRB) 4,255 (+1)
8. Maria Sharapova (RUS) 4,141 (-1)
9. Angelique Kerber (GER) 3,870
10. Dominika Cibulkova (SVK) 3,705
11. Sara Errani (ITA) 3,590
12. Ana Ivanovic (SRB) 3,455 (+1)
13. Flavia Pennetta (ITA) 3,404 (-1)
14. Caroline Wozniacki (DEN) 2,790 (+1)
15. Carla Suarez Navarro (ESP) 2,785 (-1)
16. Sloane Stephens (USA) 2,600
17. Sabine Lisicki (GER) 2,556
18. Roberta Vinci (ITA) 2,510 (+1)
19. Eugénie Bouchard (CAN) 2,490 (+1)
20. Samantha Stosur (AUS) 2,485 (-2) – Sapa-AFP