Which tennis player, Andrei Olhovskiy or Hana Mandlíková, won four Grand Slam singles titles?
Andrei Olhovskiy: Andrei Stanislavovich Olhovskiy (Russian: Андрей Станиславович Ольховский ) (born 15 April 1966) is a former tennis player from Russia, who turned professional in 1989. Hana Mandlíková: Hana Mandlíková (born 19 February 1962) is a former professional tennis player from Czechoslovakia who later obtained Australian citizenship. Hana Mandlíková:  During her career, she won four Grand Slam singles titles: the 1980 Australian Open, 1981 French Open, 1985 US Open, and the 1987 Australian Open.
Hana Mandlíková