Martina Navratilova is a person.
Martina Navratilova ( Martina Navrátilová [ ˈmarcɪna ˈnavraːcɪlovaː ] ; born Martina Šubertová [ ˈmarcɪna ˈʃubɛrtovaː ] ; October 18 , 1956 ) is a Czech and American retired tennis player and coach . She won 18 Grand Slam singles titles , 31 major women 's doubles titles ( an all-time record ) , and 10 major mixed doubles titles , marking the open-era record for most Grand Slam titles . She and Serena Williams are the only Open Era players to have won six major singles crowns without the loss of a set . Navratilova reached 11 consecutive major singles finals , second all-time to Steffi Graf 's 13 , and is the only woman ever to reach 19 consecutive major semi-finals .