Serena Falls To Petrova
, the world number one in waiting, went out of the China Open to Nadia Petrova in round three.
The American, who will take the top ranking from Dinara Safina next week after the Russian lost early in Beijing, went down 6-4 3-6 7-6 (7-5).
Petrova benefited from a dubious call on match point after seeing a 5-0 lead disappear in the tie-break. She will play Shuai Peng in the last eight.
In the men's event, world number two Rafael Nadal beat James Blake.
The Spaniard, 23, came through 7-5 6-7 (4-7) 6-3 at the Olympic tennis centre in Beijing and will face Marat Safin in the last eight.
Nadal, who beat Marcos Baghdatis on Tuesday, was playing only his second competitive match since the US Open because of an abdominal strain and was made to work hard by Blake.