Coco Gauff, Iga Swiatek both upset at Stuttgart
Tomas Kauer - News Moderator 
Top-seeded Elena Rybakina escaped in a third-set tiebreaker while No. 2 Coco Gauff and No. 3 Iga Swiatek were upset victims to Karolina Muchova and Mirra Andreeva, respectively, in Friday's quarterfinals of the Porsche Tennis Grand Prix in Stuttgart, Germany.
