Jelena Jankovic's rule as world No.1 ended today after just one week, in a switch which highlights the uncertainty in the women's game since the shock retirement of Justine Henin in May.
Serbian Jankovic will hand back the top spot to compatriot Ana Ivanovic, who will now hold it for at least the next two weeks.
The 20-year-old Ivanovic was No.1 for nine weeks (June 9-August 11) after winning the French Open, but was dethroned when injury forced her out of the Beijing Olympics where Jankovic was beaten in the quarter-finals.
Entering the Olympics, three players had a chance to capture the top ranking - Ivanovic, Jankovic and Svetlana Kuznetsova.
But an opening round loss to China's Li Na ended Kuznetsova's bid, while Jankovic was eliminated by silver medallist Dinara Safina in the last eight.
Since Henin retired on the eve of Roland Garros, three players have held the No.1 ranking - Ivanovic (11 weeks including the two weeks from Aug 18), Jankovic (one week) and Maria Sharapova (three weeks).
