1968–1976 Raised in the seaside resort of
Mar del Plata, Vilas was a
left-hander and played his first tour event in 1968. He was in the year-ending top ten from 1974 through 1982. He was a
clay-court specialist and played well on
hard-court,
grass, and
carpet surfaces. In 1974, Vilas won the year-end
Masters Grand Prix title, beating
Ilie Nastase (who was trying to win his fourth Masters title in a row) in five sets in the final on the grass of Kooyong. "Somebody asked me before what I think of grass and I say 'the grass is for cows'. Now I think some for cows and some for tennis" said Vilas afterwards. Nastase could not understand how Vilas hit so many topspin winners. In 1975 Vilas and
Bjorn Borg hit with heavy top spin in many long baseline rallies in the French Open final. Borg won in straight sets.
1977: Best year and record win streak A left-handed
baseliner, Vilas's best year on tour was 1977 when he won 16 singles titles, including two of the four major Grand Slam singles tournaments and 16 of the 31
Association of Tennis Professionals tournaments he entered. His playing record for 1977 was 130 wins against 15 losses (89.65%). Not including the Masters year-end championship, he won 72 of his last 73 ATP matches in 1977. He lost the January Australian Open final to big serving
Roscoe Tanner in straight sets. Vilas beat
Brian Gottfried in the French Open final, losing just three games. "I was powerless. Everything I tried he did something better", said Gottfried afterwards. The highest point during this run was winning the last
US Open played at
Forest Hills against
Jimmy Connors in four sets in a match where Vilas surprised his American rival by attacking the net. In 1977 he won seven consecutive titles after
Wimbledon—Kitzbühel (clay), Washington (clay), Louisville (clay), South Orange (clay), Columbus (clay),
US Open (clay) and Paris (clay)—and set up a 46-match all-surface winning streak. He also had a record 53-match winning streak on clay courts, which stood until surpassed by
Rafael Nadal in 2006. Both his winning streaks were terminated in October 1977 by
Ilie Năstase in the final of the
Raquette d'Or tournament. In that best-of-five-set final, Vilas dropped the first two sets by 6–1, 7–5 and then retired in protest of Năstase's use of a
spaghetti racquet. (The
ITF had voted to ban the racquet, but the ban did not take effect until the day after the match). After that he won a further 28 matches in a row with titles at Tehran, Bogotá, Santiago, Buenos Aires (all on clay), and Johannesburg (hard). That run was ended in the
Masters semi-finals by Björn Borg.
ATP ranking No. 1 controversy Even though he won 21 singles titles including 16 ATP titles that season, including the French Open and the US Open and was the runner-up at the January edition of the Australian Open in 1977, Vilas was never ranked by the ATP as
world No. 1 during 1977 which was due to the fact that the rankings at the time were based on the average of a player's results. He was instead ranked year-end world No. 2, behind Jimmy Connors who won 8 singles titles only (including the
Masters Grand Prix and did not win any of the 4 Grand Slam titles, but was the runner-up at Wimbledon and the US Open in 1977). Nevertheless, Vilas was rated number one by
World Tennis,
France Presse, ''Le Livre d'or du Tennis'', Gene Scott, Peter Bodo, Christian Quidet, and Michael Sutter. The International Tennis Hall of Fame inscription for Vilas stated "it was generally considered Vilas was the real No. 1 for 1977". Vilas was also rated number one by
Bud Collins and
John Barrett by the 2010s. Argentine journalist Eduardo Puppo and Romanian mathematician Marian Ciulpan investigated the 1973–78 period records, and delivered a detailed report with more than 1,200 pages in which they came to the conclusion that Vilas should have been ranked No. 1 for five weeks in 1975 as well as during the first two weeks of 1976 and handed over their research to the ATP at the end of 2014. Although the study was not refuted, in May 2015 the ATP announced it had decided not to make official the No. 1 position for Vilas because it happened in the interval between the publications of the official rankings. In October 2020, Netflix released a documentary about the controversy titled
Guillermo Vilas: Settling the Score. The documentary drew parallels with
Evonne Goolagong's recognition as world no. 1 (for two weeks in 1976) retroactively by the
WTA in 2007. In May 2024, ATP's vice-president confirmed that Vilas will never be number one. Vilas arrived in Australia in November 1978 and trained with his coach
Ion Țiriac for seven hours a day in preparation for the Australian Open in late December, in order to adapt his game to the grass courts. He beat John Marks in four sets in the final. "Vilas displayed magnificent court coverage and his adept use of the top spin lob worried Marks." The following year Vilas beat
John Sadri in the Australian Open final in straight sets to retain his title. He remarked on the tough playing conditions saying "one day it is windy and the next day it is not. The wind was harder this morning during practice, and it slowed down during the match." Vilas' last Grand Slam final was at the French Open in 1982 where he lost to
Mats Wilander in four sets. It was notable for its long rallies, the longest point taking 90 strokes.
1983–1992 By now in his thirties, on June 7, 1983, the Men's International Professional Tennis Council suspended Vilas for one year and fined him $20,000, having found that his manager and coach, Ion Țiriac, on the player's behalf, had accepted about $60,000 in appearance money from tournament promoters. Such payments were barred by the rules of the Grand Prix circuit. Vilas finished 1983 outside the top 10 at number 11. He finished 1984 ranked 28. Vilas retired from the ATP Tour in 1989 but still played on the
ATP Challenger Series until 1992. He was inducted into the
International Tennis Hall of Fame in 1991. ==Personal life==