Defending champion Eun Jeong Seong of South Korea won two matches Thursday at Ridgewood Country Club to advance to the U.S. Girls' Junior quarterfinals.

The 16-year-old Seong beat Taiwan's Yu Chiang Hou 2 and 1 in the morning, and topped Yu Sang Hou, also from Taiwan, 4 and 3 in the afternoon. Seong will face China's Xinying Wang, a 1-up winner over Hailee Cooper of Montgomery, Texas, in the round of 16.

In the other lower-bracket quarterfinal, Kendall Griffin of Sebring, Florida, will play South Korea's Yujeong Son. Griffin beat China's Jing Wen Lu 3 and 2, and Son edged Canada's Grace St. Germain in 20 holes.

Co-qualifying medalist Hye-Jin Choi of South Korea also advanced, routing Megan Furtney of South Elgin, Illinois, 7 and 6, and topping Thailand's Paphangkorn Tavatanakit 2 up. Choi will face Taiwan's Ya Chun Chang, a 6-and-5 winner over Lucy Li of Redwood Shores, California.

In the other quarterfinal, Andrea Lee of Hermosa Beach, California, will face Waverly Whiston of San Diego. Lee beat Jayna Choi of Collierville, Tennessee, 6 and 5, and Whitson edged Gina Kim of Chapel Hill, North Carolina, 1 up.