Serena Williams wins the WTA TENNIS CHAMPIONSHIP  ROUND ROBIN SERIES. She overcomes a great comeback by her big sister, Venus Williams, in the second set to win by 7-6 in one of the greatest tie breaking games of the year. Yes, the sisters put on the show of 2009, they packed the stadium, and the fans were treated with a wonderful performance by the #1 ranked player in the world,  Serena Williams, who also pocketed $1.55million dollars for her winning  performance. This win also secures that Serena will close out the year as the #1 womens tennis player of the 2009 season.