Camila Giorgi, Alison Van Uytvanck and Fiona Ferro were the three seeds to tumble at the Luxembourg Open on Tuesday.
Karolina Muchova ended Svetlana Kuznetsova's hopes early at the Kremlin Cup, while Viktoria Kuzmova was made to work in Luxembourg.
Still just 15 years old, Coco Gauff set her eyes on the best Halloween costume on the WTA Tour after claiming a reported $43,000 in Linz.
Heather Watson was defeated in straight sets by Rebecca Peterson in the final of the Tianjin Open on Sunday.
Jelena Ostapenko forced Coco Gauff into a deciding set but could not stop the brilliant 15-year-old from claiming Linz Open glory.
After beating Andrea Petkovic in straight sets at the Linz Open, reaching her first WTA Tour final, Coco Gauff hailed her rapid rise.
Coco Gauff was beaten in qualifying at the start of this week in Linz, but could claim her maiden WTA Tour singles title on Sunday.
Heather Watson has made her first WTA Tour final since March 2016, where she will meet in-form Rebecca Peterson.
Fifteen-year-old Coco Gauff achieved a number of firsts with her win over Kiki Bertens at the Linz Open.
All four semi-finalists in the Tianjin Open are unseeded after Magda Linette, Yulia Putintseva and Dayana Yastremska crashed out.