SEOUL, South Korea - In a clash of two former winners of the Korea Open, 2015 champion Irina-Camelia Begu downed 2013 champion Agnieszka Radwanska to reach the quarterfinals of the 2018 edition on Thursday.

Behind a 6-4, 6-3 victory in nearly two hours, the Romanian scored her first-ever win against the former World No.2 and Wimbledon finalist in three career meetings. 

The Romanian hadn't scored consecutive victories on tour since Roland Garros, but overcame seven double faults and losing serve four times to book a place in her third quarterfinal of the season.

Begu broke Radwanska's serve six times in the win, and won both games following another rain delay in the second set which came as she was leading 6-4, 4-3. 

Up next for Begu is a meeting with No.3 seed Maria Sakkarim who was one of four second-round winners on Wednesday.

Also advancing to the last eight was No.2 seed Kiki Bertens and Luxembourg's Mandy Minella, who defeated Dailia Jakupovic and qualifier Priscilla Hon, respectively, in straight sets.

Top seed and defending champion Jelena Ostapenko was slated to close out play on Thursday, but saw her match against Russia's Ekaterina Alexandrova pushed to Friday due to delays caused by wet weather.

The winner of that will play No.6 seed and Hiroshima champion Hsieh Su-wei in the last quarterfinal on Friday's schedule.