All Tennis Players How Many Grand Slams Has Margaret Osborne duPont Won? Margaret Osborne duPont (born Margaret Evelyn Osborne; March 4, 1918 – October 24, 2012) was a world No. 1 American female tennis player.Margaret Osborne duPont has won 6 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?
