New Zealand's world number one amateur golfer Lydia Ko has safely advanced to the quarterfinals of the United States women's amateur.
Ko scrambled out of deep rough on the 18th hole to outlast Celine Boutier of France, 1 up, in the round of 16.
It was the second tough match Ko survived after defeating American Amy Anderson in the second round.
Ko will face South African Paula Reto in tomorrow's quarterfinals.
Meanwhile medalist Hyo-Joo Kim, of Korea, was defeated in the third round at The Country Club course in Ohio.
Match-play rounds continue overnight with the four quarterfinal matches, with a 36-hole final scheduled for Monday.
All eight quarterfinalists are exempt into the 2013 U.S. Women's Amateur at the Country Club of Charleston.