Serena Williams of the USA after her tennis match against Angelique Kerber of Germany during the WTA championship in Istanbul, Turkey, Tuesday, Oct. 23, 2012. (AP Photo)

 

              Serena Williams of the USA after her tennis match against Angelique Kerber of Germany during the WTA championship in Istanbul, Turkey, Tuesday, Oct. 23, 2012. (AP Photo)
Serena Williams of the USA after her tennis match against Angelique Kerber of Germany during the WTA championship in Istanbul, Turkey, Tuesday, Oct. 23, 2012. (AP Photo)
Tags: Germany , USA