Ilie Theodoriu Năstase (born 19 July 1946) is a Romanian former professional tennis player. He was ranked as the inaugural world No. 1 in men's singles by the Association of Tennis Professionals (ATP) for 40 weeks. Năstase is one of ten players to have won over 100 total ATP-level titles, with 64 in singles and 45 in doubles, among which seven majors: two in singles, three in men's doubles and two in mixed doubles. He also won four Masters Grand Prix year-end championships. He was the first professional sports figure to sign an endorsement contract with Nike, doing so in 1972. Năstase also wrote several novels in French in the 1980s, and was inducted into the International Tennis Hall of Fame in 1991.