World number six, Karolina Pliskova became the biggest casualty at the Toray Pan Pacific Open in Tokyo after falling 6-4 6-2 to Belarusian qualifier, Aliaksandra Sasnovich.
Pliskova had been in excellent form in recent weeks- backing up her Cincinnati success with a runner-up finish at the US Open- but that run of finals has now been halted following a below-par performance on Thursday.
The Czech might not have been at her best, but her Belarusian opponent produced a confident performance to earn her first ever victory over a player ranked inside the top ten.
Next up for Sasnovich is a quarter final date with home favourite, Naomi Osaka.
Top seed, Garbine Muguruza avoided a similar fate to Pliskova’s by comfortably beating Anastasia Sevastova 6-3 6-3; thus earning some sort of revenge for her US Open loss to the Latvian, while Elina Svitolina edged out Russia’s Anastasia Pavlyuchenkova 7-6 6-4.