Serena Williams is a tennis player.
Serena Williams . Williams ' accomplishments and success in professional tennis have led some commentators , players , and sports writers to regard her as the greatest female tennis player of all time . She is also the only tennis player to have won 10 Grand Slam singles titles in two separate decades . The arrival of the Williams sisters has been credited with ushering in a new era of power and athleticism on the women 's professional tennis tour .