Czech Kvitova, who was ranked second after last month's Australian Open final defeat by Osaka, reached her third final of the year before losing to Belinda Bencic on Saturday.

Japan's Osaka remains at the rankings summit despite her shock exit to Kristina Mladenovic in her first match since winning in Melbourne.

The 21-year-old Bencic climbed 22 places to 23rd after claiming her first title since Toronto in 2015.

WTA top 20

1. Naomi Osaka (JPN)              6,871 pts

2. Simona Halep (ROM)             5,727

3. Petra Kvitova (CZE)            5,605 (+1)

4. Sloane Stephens (USA)          5,307 (-1)

5. Karolina Pliskova (CZE)        5,145

6. Elina Svitolina (UKR)          4,900

7. Kiki Bertens (NED)             4,885 (+1)

8. Angelique Kerber (GER)         4,880 (-1)

9. Aryna Sabalenka (BLR)          3,565

10. Serena Williams (USA)         3,406

11. Anastasija Sevastova (LAT)    3,325

12. Ashleigh Barty (AUS)          3,285

13. Caroline Wozniacki (DEN)      3,117 (+1)

14. Darya Kasatkina (RUS)         2,985 (-1)

15. Julia Goerges (GER)           2,780

16. Elise Mertens (BEL)           2,745

17. Madison Keys (USA)            2,726

18. Wang Qiang (CHN)              2,580

19. Caroline Garcia (FRA)         2,460 (+1)

20. Garbine Muguruza (ESP)        2,430 (-1)

Selected:

23. Belinda Bencic (SUI)          2,065 (+22)