Martina Navratilova is a person.
The 1975 Federation Cup was the 13th edition of the most important competition between national teams in women 's tennis . The Grand Slam tournaments , also called majors , are the four most-important annual tennis events . Martina Navratilova . She holds the best season win-loss record for the open era , 86-1 ( 98.9 % ) in 1983 , and four of the top six open era seasons .