Ilie Năstase, the World No. 1 tennis player between 1973 (August 23) and 1974 (June 2). He is one of the five players in history to win more than 100 ATP professional titles

Ilie Nastase born July 19, 1946, in Bucharest, Romania) is a Romanian former professional tennis player, one of the world's top players of the 1970s. Năstase was the World No. 1 tennis player between 1973 (August 23) and 1974 (June 2). He is one of the five players in history to win more than 100 ATP professional titles (57 singles and 45 in doubles). He was inducted into the International Tennis Hall of Fame in 1991. Năstase won seven Grand Slam 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 six Championship Series titles (1970–73) the precursors to the current Masters 1000. In 2005, Tennis magazine ranked him as the 28th-best player of the preceding forty years. He is the second male player to win a Grand Slam without dropping a set and the first one to achieve this feat at French Open (1973).

At the beginning of his career in 1966 Năstase travelled around the world competing with his good friend Ion Ţiriac. Together, they represented Romania in the Davis Cup competition, being three times runners up: in 1969, 1971 and 1972.
In singles, Năstase won his first tournament at Cannes on April 16, 1967. His first victories at top players happened in 1969 in Stockholm, where he defeated Tony Roche and Stan Smith.
Năstase became one of the best players in 1970, with many experts ranking him as the sixth best player in the world at that time after the Australians Rod Laver, Ken Rosewall, John Newcombe, and Roche and the American Ashe. Năstase's high ranking resulted from his success at the Italian Open in Rome and at the U.S. Indoor Open in Salisbury, Maryland. With Tiriac, Năstase won the men's doubles title at the French Open.

In 1971, Năstase was the runner-up at the French Open. where he lost the final in four sets to Jan Kodeš. In December, Năstase won his first Masters Grand Prix title.
In 1972, he became the second ranked player in the world, owing to his winning of the US Open in a five-set final over Arthur Ashe. This tournament was the only event of the year in which all the best players participated. Two months before at Wimbledon, Năstase narrowly lost to Stan Smith in an epic five sets final, one of the most exciting championship matches there. Although Smith took the title, public sympathy lay with the volatile Romanian. In the Davis Cup, Năstase was undefeated in singles until losing to Stan Smith in the final played on clay in his native Bucharest. In December at the year end tour finals, Năstase took revenge against Smith winning his second consecutive Masters Grand Prix title.

In 1973 he was in sensational form. By winning 17 tournaments, including the French Open, a doubles title at Wimbledon, a third Masters title, Năstase was the undisputed World No.1 that year. In the Davis Cup, he won 7 of 8 singles rubbers, including a victory over Tom Okker, the "Flying Dutchman." In matches against the other top players, Năstase was 1–0 against Newcombe and 1–1 against Smith. The Romanian won the French Open without dropping a set (a feat repeated by Björn Borg in 1978 and 1980 and by Rafael Nadal in 2008 and 2010), and he won the French Open (clay), Rome (clay) and Queen's Club (grass) in succession, a feat never repeated in the open era, though Borg won Rome, the French Open, and Wimbledon in succession in 1978, and Nadal won the French Open, Queen's Club, and Wimbledon in succession in 2008.
In 1974 he was the only player to qualify for both the WCT Finals and the Masters Grand Prix finals (also Newcombe played both events, although he played the Masters at Kooyong Stadium as an invitee instead of a qualifier). As usual, Năstase played well in the Masters, in particular against Newcombe in the semifinals. (Năstase finished his career with a 4–1 record versus Newcombe, losing only their first match in 1969.) The Romanian, however, lost the final to Guillermo Vilas in five sets.

For the fifth consecutive year, Năstase reached the Masters Grand Prix Final in 1975, where he defeated Björn Borg: 6–2, 6–2, 6–1.
During the first half of 1976, Năstase won four tournaments (Atlanta WCT, Avis Challenge Cup WCT, US Open Indoor, and La Costa), and head-to-head, he led Connors 2–1, Vilas 1–0, Ashe 1–0, and Borg 2–0. Năstase did not enter the Australian Open, which was again avoided by most of the top players. Năstase was prevented from entering the French Open because he participated in World Team Tennis. In the second half of the year, Nastase lost to Borg in the men's singles final of Wimbledon and in the semifinals of the US Open. Năstase won three other tournaments during the second half of the year, the Pepsi Grand Slam, South Orange, and the 4-man tournament of Caracas, Venezuela, in October (not to be confused with the Caracas WCT tournament in March), making seven tournament championships for the year. Năstase was the World No. 3, behind Connors and Borg.
In 1977 Năstase finished ninth in the ATP rankings. He was a quarterfinalist at Wimbledon and the French Open and participated in the WCT Finals. Năstase was still one of the 20 best players in 1978. At Wimbledon, he again reached the quarterfinals, losing to Okker after defeating Roscoe Tanner. During the remainder of his career, Năstase steadily declined and only occasionally defeated a good player, such as Johan Kriek in the third round of the 1982 US Open. Năstase retired from the tour in October 1985 at the age of 39 after playing in the tournament in Toulouse, although he did play the challenger tournament at Dijon in June 1988.