The 1975 Commercial Union Assurance Grand Prix was a professional tennis circuit administered by the International Lawn Tennis Federation (ILTF) which served as a forerunner to the current Association of Tennis Professionals (ATP) World Tour and the Women's Tennis Association (WTA) Tour. The circuit consisted of the four modern Grand Slam tournaments and open tournaments recognised by the ILTF. The Commercial Union Assurance Masters, Davis Cup Final and Nations Cup are included in this calendar but did not count towards the Grand Prix.
The 1974 Dutch Open was a men's tennis tournament staged at 't Melkhuisje in Hilversum, Netherlands that was part of the Group C tier of the 1974 Commercial Union Assurance Grand Prix circuit. The tournament was played on outdoor clay courts and was held from 21 July until 28 July 1974. It was the 17th edition of the tournament. First-seeded Guillermo Vilas won the singles title and earned $5,000 first-prize money. For the first time no women's events were held.
The 1974 Suisse Open Gstaad was a men's tennis tournament played on outdoor clay courts in Gstaad, Switzerland. It was the 29th edition of the tournament and was held from 8 July through 14 July 1974. The tournament was part of the Grand Prix tennis circuit and categorized in Group B. Guillermo Vilas won the singles title and the accompanying $8,000 prize money.
The 1975 Pacific Southwest Open was a men's tennis tournament played on indoor carpet courts at the UCLA Pauley Pavilion in Los Angeles, California in the United States. The tournament was classified as Grade AA and was part of the Grand Prix tennis circuit. It was the 49th edition of the tournament and ran from September 15 through September 21, 1975. First-seeded Arthur Ashe won the singles title and the $16,000 first place prize money.
The 1975 Washington Star International was a men's tennis tournament and was played on outdoor clay courts. It was categorized as an AA tournament and was part of the 1975 Grand Prix circuit. It was the seventh edition of the tournament and was held in Washington, D.C. from July 21 through July 28, 1975. Guillermo Vilas won the singles title and $16,000 prize money and a car in a final that was twice interrupted due to rain. Total attendance during the tournament was 55,000.
The 1975 U.S. Pro Tennis Championships was a men's tennis tournament played on outdoor green clay courts (Har-Tru) at the Longwood Cricket Club in Chestnut Hill, Massachusetts in the United States. It was classified as a Group AA category tournament and was part of the 1975 Grand Prix circuit. It was the 48th edition of the tournament and was held from August 19 through August 25, 1975. Second-seeded and defending champion Björn Borg won the singles title and the accompanying $16,000 first prize money. The tournament started a day late due to rain.
The 1974 Washington Star International was a men's tennis tournament and was played on outdoor clay courts. It was categorized as an AA tournament and was part of the 1974 Grand Prix circuit. It was the sixth edition of the tournament and was held at the Washington Tennis Stadium in Washington, D.C. from July 23 through July 29, 1974. Eleventh-seeded Harold Solomon won the singles title and earned $16,000 prize money in a final that was played over two days due to rain.
The 1974 Louisville Open, also known as the First National Tennis Classic, was a men's tennis tournament played on outdoor clay courts at the Louisville Tennis Center in Louisville, Kentucky, USA. It was the fifth edition of the tournament and was held from 29 July through 5 August 1974. The tournament was part of the Grand Prix tennis circuit and categorized in Group AA. The singles final was won by tenth-seeded Guillermo Vilas who received the $16,000 first prize money and 80 Grand Prix points.
The 1978 U.S. Pro Tennis Championships was a men's tennis tournament played on outdoor green clay courts (Har-Tru) at the Longwood Cricket Club in Chestnut Hill, Massachusetts in the United States. The event was part of the 1978 Grand Prix circuit. It was the 51st edition of the tournament and was held from August 21 through August 28, 1978. Despite pressure to switch to a hard court surface from the Association of Tennis Professionals (ATP) and some leading players, in line with the surface change made that year by the US Open which directly followed the Boston event, the tournament organization elected to remain a clay court tournament in 1978. Several top players including Björn Borg, Guillermo Vilas and Jimmy Connors elected not to play the tournament. Fourth-seeded and defending champion Manuel Orantes won the singles title and the accompanying $32,000 first-prize money. The final was delayed until Tuesday, August 29 due to rain.
The 1980 Italian Open was a combined men's and women's tennis tournament that was played on outdoor clay courts. For the first time in the history of the tournament the men and women competed in different locations. The men's event was held at the traditional location of Foro Italico in Rome, while the women played in Perugia. It was the 37th edition of the tournament. The men's tournament was part of the 1980 Volvo Grand Prix while the women's tournament was part of the Colgate Series. The women's event was played from 5 May through 11 May 1980 while the men's event was organized from 19 May through 25 May 1980. First-seeded Guillermo Vilas, runner-up in 1976 and 1979, won the men's singles title and the accompanying $28,000 first-prize money. The women's singles title was won by first-seeded Chris Evert-Lloyd, her third Italian Open title after 1974 and 1975.
The 1977 Washington Star International was a men's tennis tournament and was played on outdoor clay courts in Washington, D.C., USA. It was part of the 1977 Grand Prix circuit and categorized as a 4 star event. It was the 9th edition of the tournament and was held in Washington, D.C. from July 18 through July 25, 1977. First-seeded Guillermo Vilas won the singles title, his second after 1975, and earned the $20,000 first-prize money. The singles final was delayed for two hours due to rain.
The 1977 Louisville Open, also known as the Louisville International Tennis Classic, was a men's tennis tournament played on outdoor clay courts at the Louisville Tennis Center in Louisville, Kentucky, United States. It was the eighth edition of the tournament and was held from 25 July through August 1, 1977. The tournament was part of the Grand Prix tennis circuit and categorized as a Four Star event. The singles final was won by first-seeded Guillermo Vilas who received $20,000 first prize money. It was Vilas' third title win at the tournament after 1974 and 1975.
The 1978 Suisse Open Gstaad was a men's tennis tournament played on outdoor clay courts in Gstaad, Switzerland. It was the 33rd edition of the tournament and was held from 10 July through 16 July 1978. The tournament was part of the Grand Prix tennis circuit with a total prize money available of $75,000. First-seeded Guillermo Vilas won the singles title, his second at the tournament after 1974.
The 1979 Louisville Open, also known as the Louisville International Classic, was a men's tennis tournament played on outdoor clay courts at the Louisville Tennis Center in Louisville, Kentucky, United States. It was the tenth and final edition of the tournament and was scheduled from Monday, July 23 through Sunday, July 29, 1979 but due to intermittent rain throughout the week it ended one day late. Some matches were played on indoor clay courts. The tournament was part of the Grand Prix tennis circuit. The singles final was won by seventh-seeded John Alexander, last year's runner-up, who received $25,000 first prize money and earned 175 ranking points.
The 1982 Cuore Cup was a men's tennis tournament played on indoor carpet courts at the Palazzo dello Sport in Milan, Italy. The event was part of the Super Series tier of the 1982 Volvo Grand Prix circuit. It was the fifth edition of the tournament and was held from 22 March through 28 March 1982. Second-seeded Guillermo Vilas won the singles title an earned $70,000 first prize money. He entered the tournament on a wildcard after John McEnroe, the winner of the three previous editions, withdrew due to an ankle injury.
The 1983 United Virginia Bank Classic, also known as the Richmond WCT, was a men's tennis tournament played on indoor carpet courts at the Robins Center in Richmond, Virginia, United States. The event was part of 1983 World Championship Tennis circuit. It was the 18th edition of the tournament and was held from February 7 through February 13, 1983. Second-seeded Guillermo Vilas won the singles title and the $100,000 first-prize money.
The 1978 Mutual Benefit Life Open, also known as the South Orange Open, was a men's tennis tournament played on outdoor clay courts at the Orange Lawn Tennis Club in South Orange, New Jersey in the United States. The event was part of the 1978 Grand Prix circuit. It was the ninth edition of the tournament and was held from July 31 through August 6, 1978. First-seeded Guillermo Vilas won his second consecutive singles title at the event and earned $15,000 first-prize money.
The 1975 City National Buckeye Championships was a men's tennis tournament played on outdoor hard courts at the Buckeye Boys Ranch in Grove City, Columbus, Ohio in the United States that was part of Group B category of the 1975 Grand Prix circuit. It was the sixth edition of the tournament and was held from August 12 through August 18, 1975. Fourth-seeded Vijay Amritraj won the singles title and earned $9,000 first-prize money.
The 1977 Wendy's Tennis Classic, also known as the Buckeye Championships, was a men's tennis tournament played on outdoor clay courts at the Muirfield Village in Dublin, a suburb of Columbus, Ohio in the United States that was part of the Four Star category of the 1977 Grand Prix circuit. It was the eight edition of the tournament and was held from August 8 through August 15, 1977. First-seeded Guillermo Vilas won the singles title and earned $20,000 first-prize money.
The 1976 St. Louis Tennis Classic, also known as the St. Louis WCT, was a men's professional tennis tournament that was part of the Blue Group of the 1976 World Championship Tennis circuit. It was played on indoor carpet courts at the Kiel Auditorium in St. Louis, Missouri in the United States. It was the sixth edition of the tournament and was held from February 17 through February 22, 1976. First-seeded Guillermo Vilas won the singles title and earned $17,000 first-prize money.
Guillermo Vilas [1] 
Wojciech Fibak / 
Anand Amritraj / 