Three scores of 1 in ends 6, 7 and 8 secured a 6-3 win for Kubeška against Baumann of Germany.
A strong score of 3 for Šik in end 5 wasn't enough to shake off a strong Team Mouat, who make up one half of an all Scottish semi final clash.
GSCT leaders proceed to the semi finals once more, after a comfortable 6-2 win over Team Schwaller in their quarter final.
Stjerne v Kubeška and Mouat v Hardie semi finals are underway now at Murrayfield. Kubeška and Mouat have hammer in their respective matches.