Seoul: Slovakian second seed Anna Karolina Schmiedlova advanced on Wednesday to the quarter-final of the WTA Korea Open after a tough bout with Christina McHale of the United States.
Schmiedlova, ranked 31st in the world, needed three sets to oust McHale 6-2, 4-6, 6-3.
Belgium`s Alison Van Uytvanck, seeded eighth, took a tiebreaker to win the third set against Katerina Siniakova of the Czech Republic 6-3, 1-6, 7-6 (7/3).
Swedish veteran Johanna Larsson, ranked 62nd in the world, booked her place in the quarter-final with an upset victory over German seventh seed Julia Goerges 7-5, 6-4.
German fifth seed Mona Barthel crushed Mariana Duque of Colombia 6-2, 6-1.