Cristian Garin saved two match points en route to shocking Alexander Zverev and ending the German's reign at the Munich Open on Friday.
The Chilean earned the first top-five scalp of his career against the two-time defending champion in a 6-4 5-7 7-5 triumph on the clay.
Garin saw three match points go begging when serving at 5-4 in the second set and was staring down the barrel when Zverev had chances to see out the match himself at 5-4 up in the decider.
But incredibly Garin won 12 of the last 13 points to earn the upset win and book a semi-final date with Marco Cecchinato, who saved a match-point of his own in a comeback 1-6 7-5 7-5 win over Marton Fucsovics.
Three-time Munich champion Philipp Kohlschreiber was sent packing in three sets by Matteo Berrettini, who will now face fourth seed Roberto Bautista Agut after the Spaniard also lasted the distance to see off Guido Pella.
At the Estoril Open, Stefanos Tsitsipas made it into the last four for the second straight year with a gutsy 7-6 (7-3) 6-4 success against Joao Domingues.
David Goffin is next for the Greek up-and-comer, with the Belgian seeing off Malek Jaziri 4-6 7-6 (7-4) 6-2 in a match lasting over two and a half hours.
Alejandro Davidovich Fokina is also into the last four after upsetting third seed Gael Monfils in three sets and will face Pablo Cuevas after his 6-0 6-7 (5-7) 6-2 beating of Frances Tiafoe.