Serena Williams of the United States stays top while Stuttgart semi-finalist Simona Halep of Romania gains a place to
fourth in the latest WTA women's tennis rankings.
Angelique Kerber of Germany missed a chance to regain top spot after she went out in her first match at the Stuttgart tournament, won on Sunday by Germany's Laura Siegemund.

WTA top 10 as of May 1 (previous rankings in parenthesis):
(1) Serena Williams, United States, 7,010 points
2 (2) Angelique Kerber, Germany, 6,925
3. (3) Karolina Pliskova, Czech Republic, 6,010
4. (5) Simona Halep, Romania, 5,021
5. (4) Dominika Cibulkova, Slovakia, 5,065
6. (6) Garbine Muguruza, Spain, 4,691
7. (7) Johanna Konta, Britain, 4,330
8. (8) Agnieszka Radwanska, Poland, 4,205
9. (9) Svetlana Kuznetsova, Russia, 4,015
10. (10) Madison Keys, United States, 3,857.