Qualifier Joao Sousa reached the Topshelf Open semi-finals in 's-Hertogenbosch as the Portuguese world No 48 brushed aside Dutchman Thiemo de Bakker 6-4 6-2.
Sousa has benefited from the withdrawal of world No 7 and 2012 David Ferrer, his scheduled first round opponent who pulled out with a stomach virus on the eve the tournament.
He will now face Germany's Benjamin Becker, who came back from a set down to defeat Canadian Vasek Pospisil 6-7 (3-7) 7-6 (7-5) 6-4 in a fiercely-contested match that was briefly interrupted by rain.
In the women's draw, Slovakia's Magdalena Rybarikova advanced to the last four with a 6-2 7-5 win over Germany's Annika Beck.
Beck, who knocked out defending champion and world No 3 Simona Halep of Romania, came up short against the world No 39 who is chasing a fifth WTA title.
China's Zheng Jie awaits in the semi-finals after she crushed Ukraine's Elina Svitolina 6-3 6-0.
And eighth seed Klara Zakopalova advanced easily by defeating Kazakhstan's Yaroslava Shvedova 6-2 6-4.
She will take on American Coco Vandeweghe, who won a tense first set tie-break before prevailing 7-6 (7-3) 6-1 over Spaniard Garbine Muguruza.