Christine Marie ""Chris"" Evert (born 21 December 1954) is a umwhile Warld No. 1 profeesional tennis player frae the Unitit States. She wan 18 Grand Slam singles championships, includin a record seiven championships at the French Open an a record sax championships at the U.S. Open. She wis the year-endin Warld No. 1 singles player in 1974, 1975, 1976, 1977, 1978, 1980, an 1981.