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, ousted McHale in three sets 6-2, 4-6, 6-3. In the first set, Schmiedlova played well and won it 6-2 but McHale bounced back in style and won second set 6-4. Schmiedlova then showed her class and won the decisive set 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 booked her place in the quarter-final with an upset victory over German 7th seed Julia Goerges 7-5, 6-4. German 5th seed Mona Barthel crushed Mariana Duque of Colombia 6-2, 6-1.