Tennis pros Serena and Venus Williams have a serious case of sibling rivalry. On September 7, Serena Williams beat big sister Venus to win the U.S. Open. She is the sixth woman in history to win three major tennis championships in a row. Serena is now the top female tennis player in the world. She bumped Venus down to second place after winning Wimbledon in July. "Everyone has their year, and this is hers," Venus, 22, said of Serena, who is only 15 months younger. Which Williams sister will be on top in 2003?