All Tennis Players How Many Grand Slams Has Gustavo Kuerten Won? Gustavo “Guga” Kuerten (born 10 September 1976) is a Brazilian former world No. 1 tennis player.Gustavo Kuerten has won 3 Grand Slams. FacebookTwitterEmail How Many Grand Slams Has Madison Keys Won? How Many Grand Slams Has Jannik Sinner Won? How Many Majors Has John Isner Won?