MADRID, Nov 7 (Reuters) Serena Williams was forced to pull out of her opening match of the WTA Championships in Madrid with an injury today.
The 26-year-old American had just lost the first set against Russian Anna Chakvetadze 6-4 but retired as the second set was about to start.
She had called for the doctor to attend a problem with her left knee when the score was 5-4, having looked short on mobility throughout the opening set. She played on with strapping around the knee but did not look happy.
Serena's withdrawal from the match means world number one Justine Henin, who has won her first two outings in the yellow group, has automatically qualified for the semi-finals.
REUTERS MP AS0217