Danka Kovinic brought Monica Puig's season to an end by beating the Olympic singles champion in straight sets to move into the semi-finals of the Tianjin Open on Friday.
Fifth seed Puig is ranked 30 places above Montenegrin Kovinic, but it was the world number 63 who came out on top with a 6-4 6-3 victory.
Puig was broken four times and could only muster a first-serve percentage of 54 in what will be the final competitive game of the year for the Puerto Rican.
Last year's runner-up Kovinic will face Peng Shuai in the last four after the home contender was given a walkover following defending champion Agnieszka Radwanska's withdrawal due to a thigh injury.
Second seed Svetlana Kuznetsova is the highest-ranked player remaining in the tournament as a result of the world number eight's 2-6 6-4 7-6 (7-3) win against Naomi Osaka.
Kuznetsova, who started the week still in the hunt for a WTA Finals spot, will take on Alison Riske after the American saw off Han Xinyun 6-3 6-3.