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).