World number one Dinara Safina was upset 7-5, 7-6 by local wild card Zhang Shuai in the second round of the China Open, leaving Serena Williams one victory away from reclaiming top spot in the rankings.
Serena's sister Venus, the world number three, also had a bad day, losing to Russia’s Anastasia Pavlyuchenkova for the second week in a row, this time 3-6, 6-1, 6-4.
Serena just needs to beat Ekaterina Makarova in her second round match at the Olympic tennis centre on Tuesday to move up from number two after Safina crumbled in the face of a fierce onslaught from the 226th ranked Zhang.
Safina, who lost her opening match at last week's Pan Pacific Open to a qualifier, made 20 unforced errors and 12 double faults before leaving the centre court in tears. Her post-match news conference was cancelled.
Earlier, Novak Djokovic became the first seed to reach the men's second round with an unconvincing 6-3, 7-5 victory over Victor Hanescu.