Grand slam title winners Stan Wawrinka and Marin Cilic were beaten in the Geneva Open quarter-finals by unseeded opponents on Thursday.
Top-seeded Stan Wawrinka, ranked No.9, went down 6-7 (5-7) 6-4 6-4 to 74th-ranked Federico Delbonis of Argentina.
The 2014 Australian Open champion extended an unwanted record of never having won a tour title in his native Switzerland.
In the semi-finals, Delbonis will play sixth-seeded Joao Sousa of Portugal, who rallied to a stunning victory against Pablo Andujar of Spain 6-4 2-6 7-6 (8-6).
Sousa faced four match points trailing 6-2 in the decisive tiebreaker then reeled off six straight points to take victory.
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Second-seeded Cilic was beaten 7-5 6-3 by Santiago Giraldo of Colombia.
Cilic, who has been troubled by a shoulder injury this year, has advanced to only one tournament semi-final since winning the US Open title last September.
The 10th-ranked Croatian had nine aces on the clay-court surface but failed to create a break-point chance against the 67th-ranked Giraldo.
Giraldo will play Thomaz Bellucci of Brazil in an all-unseeded semi-final.
Bellucci, a two-time champion at the neighboring Swiss Open in Gstaad, beat Albert Ramos-Vinalos of Spain 6-0 1-6 6-3.
