Clark Edward Graebner (born November 4, 1943) is an American former professional tennis player.
He was four times a world top ten ranked player each year from 1966 to 1969, reaching world No. 3 in 1967 and world No. 7 the following year. He was ranked eight times in the top ten U.S. players by the USTA, reaching U.S. No. 2 in 1968 behind Arthur Ashe, and U.S. No. 3 in 1966 and 1971.
Graebner won three U.S. national titles, the U.S. Clay Court in 1968, the U.S. Hard Court in 1969, and the U.S. Indoor in 1971. He was a member of the U.S. Davis Cup team which won the Davis Cup in five straight years from 1968 to 1972.
He won a Grand Slam doubles title at the 1966 French Championships at Roland Garros with doubles partner Dennis Ralston.
Graebner was born in Cleveland, Ohio, the only child of Paul Graebner, a dentist, and his wife, the former Janice Clark. Paul had been a moderately successful youth player. Clark won the state high-school tennis championship three times. He graduated from Northwestern University, where he joined the Delta Upsilon fraternity.
In 1964 he married rising American tennis player Carole Caldwell. They had two children, a daughter, Cameron, and a son, Clark. The couple separated in 1974 and eventually divorced. In 1975, Graebner married Patti Morgan. Caldwell died of cancer in New York City on November 19, 2008.
Graebner won his first important international tournament in December 1965 at the Victorian Championships at Melbourne's Kooyong Stadium. He defeated Ray Ruffels, Tony Roche in a close five set match, Herb Fitzgibbon, Fred Stolle, and Roy Emerson in a five set final.
Graebner lost to John Newcombe in the quarterfinal of the Australian Open. He returned the favour by defeating Newcombe in the third round at the French Championships at Roland Garros that season. He won the men's doubles title at the French Championships, with his doubles partner Dennis Ralston, defeating the Rumanian doubles team of Tiriac/Năstase in the final.
Graebner won the Pennsylvania Lawn Tennis Championships at the Merion Cricket Club defeating Charlie Pasarell in the semifinal and Stan Smith in the final. At the U.S. Championships at Forest Hills, New York he reached the quarterfinals where he was defeated by Stolle, who would win the title that year.
Graebner was ranked world No. 9 for 1966 by McCauley. He was ranked the No. 3 U.S. player for that year by the USTA.
Graebner won the Buffalo Indoor Tennis Championships in February defeating Marty Riessen in a marathon final. Graebner would also win this same event in 1968 (over Riessen again in the final), in 1969 (over Mark Cox in the final) and in 1970 (over Bob Lutz in the final).
He lost to Newcombe, the champion that year, in the 4th round of the 1967 Wimbledon championships. In the 1967 United States Championship, the last time the event, today's U.S. Open, was open only to amateur players, Graebner was the top-seeded U.S. player at No. 7. He defeated the No. 2 seed Roy Emerson in a marathon quarterfinal, but lost in the final to Newcombe.
Graebner was ranked world No. 3 for 1967, which would be his highest world ranking, by the Martini and Rossi panel of tennis experts using a point system for tournament play. He was ranked the U.S. No. 4 by the USTA for that year.
In 1968 he reached the final of the Queen's Club Championships in London, defeating Stolle, Emerson and Alex Metreveli, but the final was not played. Graebner then reached the semifinals in singles at the 1968 Wimbledon, defeating both Manuel Santana and Stolle, before losing a close match to Roche. He won the 1968 U.S. Men's Clay Court Championships in Milwaukee defeating Charlie Pasarell in the semifinal and Stan Smith in the final. At the inaugural US Open, he defeated Newcombe in the quarter-final, but lost the semifinal to Arthur Ashe, the eventual champion. John McPhee's book, Levels of the Game, is about a semifinal match played between Graebner and Ashe at the 1968 US Open at Forest Hills. Ashe won the match.
Graebner was ranked U.S. No. 2 by the USTA for 1968 and world No. 7 by Lance Tingay as well as by most other ranking authorities.
Graebner and Ashe led the U.S. Davis Cup team to victory in the 1968 Davis Cup, its first in five years. Graebner won both of his singles matches in the Challenge Round against Australia, defeating Bill Bowrey and Ruffels in five set matches. The Americans won four more titles in as many years.
Graebner won seven tournaments in the 1969 season, beginning with the Richmond WCT Indoor in February, defeating Thomaz Koch (winner over both Ashe and Richey in the event) in the final. He won the New York Indoor in March, defeating Pasarell in the final. At Wimbledon in 1969, Graebner defeated Ilie Năstase and Andrés Gimeno before losing to Roche again in the quarterfinal, this time in a marathon five sets. He won the U.S. Hard Court Championships in Sacramento in June, defeating Erik van Dillen in a close five-set final. That same season, Graebner won the Southampton Invitational at Long Island on grass, defeating Bill Bowrey in the semifinal and Lutz in the final, both matches in three straight sets. At the U.S. Open that year, he retired in the third set against Roger Taylor in the second round.
Graebner was ranked world No. 10 for 1969 by the Daily Express. He was ranked the U.S. No. 4 player by the USTA ranking.