The Romanian, who took third place the week before having won the tournament in Dubai, lost to Caroline Wozniacki in Germany.
Sharapova was already assured of losing the second placed-ranking when she went down to eventual tournament winner Angelique Kerber in her first match of the season on clay.
Former top tenner Kerber is back up to 12th following back-to-back tournament wins in Stuttgart and Charleston.
Serena Williams remains comfortably ahead at the top of the rankings ahead of the French Open in Paris which starts on May 24.
WTA world rankings
1. Serena Williams (USA) 9.981 pts
2. Simona Halep (ROM) 7.755 (+1)
3. Maria Sharapova (RUS) 7.525 (-1)
4. Petra Kvitová (CZE) 6.060
5. Caroline Wozniacki (DEN) 4.790
6. Eugenie Bouchard (CAN) 4.122 (+1)
7. Ana Ivanovic (SRB) 4.000 (-1)
8. Ekaterina Makarova (RUS) 3.465
9. Agnieszka Radwanska (POL) 3.345
10. Carla Suárez (ESP) 3.335
11. Andrea Petkovic (GER) 3.260
12. Angelique Kerber (GER) 3.230 (+2)
13. Lucie Safárová (CZE) 2.895
14. Karolína Plísková (CZE) 2.875 (-2)
15. Sara Errani (ITA) 2.720
16. Venus Williams (USA) 2.591
17. Madison Keys (USA) 2.325
18. Jelena Jankovic (SRB) 2.140
19. Sabine Lisicki (GER) 2.127
20. Garbiñe Muguruza (ESP) 2.075