Teenager Dominic Stephan Stricker produced the shock of the day at the Stuttgart Open as he knocked out second seed Hubert Hurkacz in the round of 16.
The 18-year-old wildcard, ranked 335 in the world, claimed a straight sets victory courtesy of tie-breaks, as had been the case in his previous outing against Radu Albot.
And his reward for a 7-6 (7-5) 7-6 (7-5) win over a man placed 315 places higher than him in the men's rankings is a quarter-final tie against Sam Querrey.
The American sealed his passage into the last eight by beating qualifier James Duckworth 6-4 7-6 (9-7) on Thursday.
Top seed Denis Shapovalov's place in the next round remains in doubt going into Friday after the Canadians clash with Feliciano Lopez was cut short by rain with both men having taken a set.
The winner of that final set will face former world number three Marin Cilic, who comfortably beat Nikoloz Basilashvili 6-3 6-2.
Another Canadian also remains in the draw in the form of third-seeded Felix Auger-Aliassime after his 6-3 7-6 (7-4) win over Lloyd Harris.
There, he will face sixth seed Ugo Humbert after his straight sets win over wildcard entry Yannick Hanfmann.
The quarter-final line-up is completed by fourth seed Alex de Minaur, who beat compatriot Jordan Thompson, and Jurij Rodionov, whose progress was aided by Peter Gojowczyk's first-set retirement.