Top seed Tatjana Maria was sent packing by Chilean qualifier Daniela Seguel on a rain-ravaged day at the Bogotá Open.
Maria suffered a shock 6-3 6-1 loss on Thursday as world number 191 Seguel reached her first WTA Tour quarter-final in Bogotá, where only two matches were completed due to wet weather.
Seguel had become the first Chilean woman to win a WTA match since Silvana Urroz in 1980 after defeating Nicole Gibbs in her Bogota opener.
And Seguel continued where she left off against Maria, dropping just four games in a convincing performance against the highly-fancied German.
"I'm very happy I achieved the most important win of my career," Seguel said. "I've been feeling better as days go by since I arrived Bogota.
"I'm really proud because I work every day to make history for my country. It's also a motivation for me to keep improving my WTA ranking; it was one of the main objectives for this part of the season. All the effort is dedicated to my father. After he died, my only motivation is him."
Standing in the way of Seguel and the semi-finals is either seventh seed Ana Bogdan or Anna Blinkova.
Bogdan's clash with Blinkova was postponed at 2-2 in the final set due to rain at the tournament.
After dropping the opening set 6-1, Bogdan rallied to win the second-set tie-break 10-8.
Magda Linette – the second seed - was also leading Maria Herazo Gonzalez 6-2 3-1 when play was abandoned.
Meanwhile, the only other match completed saw third seed Johana Larsson outlast qualifier Valentini Grammatikopoulou 4-6 6-4 6-4.