SEOUL, South Korea — Second-seeded Kiki Bertens advanced to the quarterfinals of the rain-hit Korea Open by beating Dalila Jakupovic 6-4, 7-5 Thursday.

Bertens broke the Slovenian player's serve at 5-5 in the second set and held in the next game.

Also, Mandy Minella beat Australian qualifier Priscilla Hon 6-4, 6-3. The 20-year-old Hon was trying to make it to the Seoul quarterfinals for the second straight year as a qualifier.

Persistent rain throughout the afternoon delayed the start of four second-round matches.

A match between two former champions, Agnieszka Radwanska and Irina-Camelia Begu, was suspended late Thursday with Begu leading 6-4, 4-3. When play resumed, Begu completed a 6-4, 6-3 win.

Rain postponed a match between top-seeded Jelena Ostapenko, the 2017 French Open champion, and Ekaterina Alexandrova. It was scheduled to be played Friday along with four quarterfinals.