The top two seeds were eliminated in the second round of the Pan Pacific Open in Tokyo as Paula Badosa and Caroline Garcia both crashed out on Wednesday.
Badosa was defeated in just 78 minutes by Zheng Qinwen, with the number one seed going down 6-3 6-2.
It was 19-year-old Zheng's first completed win against a top 10 opponent in her career, and she said afterwards: "Even though the score was like this, there were a lot of emotions for me in this match and I'm very proud of myself. It's not a surprise. I always knew I had the level, I just had to make it."
Second seed Garcia hit 27 aces in her match against Zhang Shuai, the most in a single WTA-level contest since Kristyna Pliskova against Monica Puig in Luxembourg 2019 (28), but it was not enough as she lost two tie-breaks to lose 4-6 7-6 (7-5) 7-6 (7-5).
Number three seed Garbine Muguruza had more success as she beat Greek opponent Despina Papamichail 6-4 6-2, while Claire Liu also eased to a win against Elise Mertens 6-4 6-1, and will play Zheng in the quarter-finals.
Eighth seed Elena Rybakina suffered a first-round exit as she lost to Liudmila Samsonova 6-2 6-4, who will play Xinyu next.
The seeds fared better over at the Korea Open, with Emma Raducanu sealing a first-round win against Moyuka Uchijima 6-2 6-4, while Magda Linette also eased past Arianne Hartono, 6-2 7-5, though fifth-seed Varvara Gracheva was knocked out by Anna Blinkova 6-4 7-6 (7-1).
In the second round, third seed Ekaterina Alexandrova is through after beating Han Na-lae 6-1 6-3, as is Lin Zhu of China following her straightforward 6-1 6-3 victory against India's Ankita Raina.
There were also wins for Tatjana Maria against Kimberly Birrell, and 17-year-old Andorran Victoria Jimenez Kasintseva against eighth seed Rebecca Marino.