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
Grand Slam Cup added in 1998 and was held simultaneously with the men's Cup. Throughout its existence, the Grand Slam Cup was famous for paying out the highest prize money of any tournament in tennis. The winner for the first three years of the Cup received U.S.$2 million in prize money, which dipped to $1.625 million in 1993, rose to $1.875 million in 1996 and back to $2 million in 1997 before falling to $1.3 million in 1998. If the Cup was won by a player who had also won a Grand Slam event that year they received a bonus of $1 million.