Third seed Kaia Kanepi eased into the quarter-finals of the KDB Korea Open with a straight-sets win over Galina Voskoboeva in Seoul.
Estonian Kanepi, making her return this week after more than three months out with an Achilles injury, was never troubled by her opponent and sealed a routine 6-2 6-2 victory in one of only two second-round matches played on Wednesday.
The other contest saw Kiki Bertens of the Netherlands produce a superb comeback after being comprehensively beaten in the first set to see off Sílvia Soler-Espinosa 1-6 7-6 (7-3) 6-2.
The surprise of the day was the exit of second seed Maria Kirilenko.
The Russian was forced to retire hurt due to a back injury with the score at 1-1 in the first set against local wildcard Lee So-ra.
But Kirilenko's compatriot and fourth seed Nadia Petrova had no such difficulties, the former French Open semi-finalist dispatching Lourdes Domínguez Lino of Spain 6-2 6-4.
Another Spaniard to exit was Carla Suarez Navarro as she fell to a 7-6 (10-8) 6-3 defeat against Austria's Tamira Paszek.
The day's other first-round match was won by Maria Jose Martinez Sanchez, who beat qualifier Eleni Daniilidou 6-2 6-3.