Grand Slam (tennis) tennis ball, Martina Navratilova finally did it." Although the ITF recognizes what is now unofficially known as the "non-calendar year Grand Slam" on its Roll of Honour, no subsequent player to win four or more majors in a row—Steffi Graf, Serena Williams, or Novak Djokovic—has received bonus prize money. Combining "the" Grand Slam and non-calendar year Grand Slam, the total number of times that players achieved the feat (of being the reigning champion in all four majors) expands to 18. Three women have won four or more consecutive major titles since 1970, with Navratilova taking six in a row in
International Tennis Federation ITF organizes the Grand Slam events, annual team competitions for men (Davis Cup), women (Fed Cup), and mixed teams (Hopman Cup), as well as tennis and wheelchair tennis events at the Summer Olympic and Paralympic Games on behalf of the International Olympic Committee. The ITF sanctions the Grand Slam tennis tournaments as well as circuits which span age ranges (junior, professional men and women, and seniors) as well as disciplines (wheelchair tennis; beach tennis). In addition to these circuits, the ITF also maintains rankings for juniors, seniors, wheelchair and beach tennis. Duane Williams, an American who lived in Switzerland, is