Serena Williams (R) and her sister Venus Williams of the United States pose for pictures before their ladies' singles final at the 2009 Wimbledon Tennis Championships at the Centre Court in Wimbledon of London July 4, 2009. [Xinhua/Wang Lili]

Serena Williams of the United States reacts during the ladies' singles final against her sister Venus Williams at the 2009 Wimbledon Tennis Championships at the Centre Court in Wimbledon of London July 4, 2009. [Xinhua/Wang Lili]