Günthardt was the coach of Steffi Graf from the start of 1992 until the end of Graf's tennis playing career in July 1999, and he also worked briefly with Jelena Dokić and Jennifer Capriati.
Günthardt bol trénerom nemeckej tenistky Steffi Grafovej od začiatku roka 1992 do konca jej kariéry v júli 1999, veľmi krátko pracoval aj s Jelenou Dokićovou a Jennifer Capriatiovou.