Paris - Japan's Naomi Osaka maintained a slender lead over Romanian Simona Halep at the top of the WTA Tour rankings released on Monday.

Osaka now sits 185 points ahead of Halep, with Czech pair Petra Kvitova and Karolina Pliskova in third and fourth.

American Madison Keys, winner of the WTA event in Charleston last week, jumped four spots to 14th.

Top 20 in the latest WTA Tour rankings:

1. Naomi Osaka (JPN) 5 967

2. Simona Halep (ROM) 5 782

3. Petra Kvitova (CZE) 5 645

4. Karolina Pliskova (CZE) 5 580

5. Angelique Kerber (GER) 5 220

6. Elina Svitolina (UKR) 5 020

7. Kiki Bertens (NED) 4 640

8. Sloane Stephens (USA) 4 386

9. Ashleigh Barty (AUS) 4 275

10. Aryna Sabalenka (BLR) 3 595

11. Serena Williams (USA) 3 461

12. Caroline Wozniacki (DEN) 3 421

13. Anastasija Sevastova (LAT) 3 145

14. Madison Keys (USA) 3 011

15. Anett Kontaveit (EST) 2 845

16. Wang Qiang (CHN) 2 812

17. Elise Mertens (BEL) 2 800

18. Julia Görges (GER) 2 630

19. Garbine Muguruza (ESP) 2 525

20. Belinda Bencic (SUI) 2 515