Serena Williams of the U.S. celebrates after defeating Russia’s Zvonareva in their women’s singles tennis match at the All England Lawn Tennis Club during the London 2012 Olympic Games

Serena Williams breezed into the semifinals with another comfortable win. (Sergio Moraes/Reuters)

Serena Williams breezed into the semifinals with another comfortable win. (Sergio Moraes/Reuters)

Serena Williams of the U.S. celebrates after defeating Russia’s Vera Zvonareva in their women’s singles tennis match at the All England Lawn Tennis Club during the London 2012 Olympic Games August 1, 2012. REUTERS/Sergio Moraes (BRITAIN – Tags: OLYMPICS SPORT TENNIS TPX IMAGES OF THE DAY)