Top seed Kiki Bertens rallied to top Alison Van Uytvanck 4-6, 6-3, 6-3 on Thursday at the Upper Austria Ladies Linz.
With the win, Bertens will meet American teenager Coco Gauff on Friday in the quarterfinals.
Bertens, from the Netherlands, started slowly but used the strength of her serve to defeat her Belgian opponent. Bertens won 84 percent of her first-serve points to prevail in the nearly two-hour match.
In other action, Kristina Mladenovic of France upset fourth-seeded Croatian Donna Vekic 3-6, 6-2, 6-2, and No. 8 Ekaterina Alexandrova of Russia toped Laura Siegemund of Germany 7-6 (1), 2-6, 6-4.
Slovakia’s Viktoria Kuzmova came from behind to upset No. 9 seed Anastasia Pavlyuchenkova of Russia 2-6, 6-2, 6-4.
Unheralded Heather Watson earned her biggest victory since 2017, dominating home-country favorite and No. 2 seed Wang Qiang 6-3, 6-0 to advance to the quarterfinals in China.
Watson, of Great Britain, hadn’t won a hard-court match for more than a year before arriving in Tianjin. She hadn’t defeated an opponent ranked in the top 30 since beating Latvia’s Anastasija Sevastova at Wimbledon in 2017.
Watson will face Magda Linette of Poland, the No. 8 seed who was up 4-0 in the first set when Kurumi Nara of Japan retired.
Also retiring was seventh seed Zheng Saisai of China, who lost the first five games of the first set to unseeded Veronika Kudermetova of Russia. Third-seeded Dayana Yastremska of Ukraine advanced with a 6-2, 6-4 decision over China’s Shuai Peng.
—Field Level Media