Ilie Theodoriu Năstase is a Romanian former world No. 1 tennis player. He was ranked world No. 1 in singles from 23 August 1973 to 2 June 1974, and was the first man to hold the top position on the computerized ATP Rankings. Năstase is one of the 10 players in history who have won over 100 total ATP titles, with 64 in singles and 45 in doubles.
Năstase won seven major titles: two in singles, three in men's doubles and two in mixed doubles. He also won four Masters Grand Prix year-end championship titles and seven Grand Prix Super Series titles, the precursors to the current Masters 1000. He was the first professional sports figure to sign an endorsement contract with Nike, doing so in 1972. Năstase wrote several novels in French in the 1980s, and was inducted into the International Tennis Hall of Fame in 1991.