Top seed Belinda Bencic was sent tumbling out of the Luxembourg Open after a straight-sets defeat to emerging Russian Ludmilla Samsonova.
The world number 12, who was beaten by Emma Raducanu in the last eight of the US Open, fell again the last eight as she was beaten 6-1 6-4.
It was the second successive defeat for Bencic against the Russian, having also lost their final at the Berlin Open in June.
There was a further upset as Belgium’s second seed Elise Mertens lost 7-5 6-2 to fifth seed Marketa Vondrousova of the Czech Republic.
Third seed and former French Open champion Jelena Ostapenko reached the last four with a 7-6 (6) 6-2 win over Alize Cornet, while Canada’s Clara Tauson saw off Marie Bouzkova 6-3 6-2.
In Portoroz, fourth seed Sorana Cirstea – another recent Raducanu conquest – was beaten 6-4 4-6 6-1 by Italy’s Jasmine Paolini in their last eight meeting.
She will next face second seed Yulia Putintseva who beat Lucia Bronzetti 6-3 6-2, while third seed Alison Riske saw off Kristina Mladenovic 6-4 6-1.
Riske will face Kaja Juvan, who came through her all-Slovenian battle with Tamara Zidansek 7-6 (4) 6-3.
