Ana Ivanovic of Belgrade, Serbia.
According to espn.com, as of January 14, 2008 the second ranked woman tennis player in the world is Svetlana Kuznetsova of Russia.
currently Roger Federer is the world's number one men's tennis player, followed by Nadal and Djokovic
Pete Sampras, a professional tennis player, was ranked as the world's number 1 tennis player in 1993. He held that position for nineteen consecutive weeks.
As of 3/19/2010, Serena Williams
As of March 2012: Novak Djokovic.