Tseng, who defeated Michelle Wie in the final last year, advances to play Juli Wightman in the quarterfinals Friday morning. Wightman rolled to a 5 and 4 win in the third round over Kailin Downs. Wightman downed second-seeded Angela Park in the second round.
Mari Chun, who shared medalist honors with Park, remained alive after a pair of hard fought matches. She beat Renee Skidmore in round two and Hannah Jun in the third round by identical 1-up scores.
Jane Rah handled Shannon Johnson, 4 and 3, in the third round and will face Chun in the quarterfinals.
Amie Cochran romped to a 5 and 4 win in the second round, then bested Marina Choi 2 and 1 in round three. She will face Tiffany Chudy on Friday.
Chudy needed 20 holes to win her first match before hanging on for a 2 and 1 win over Tiffany Lua in the third round.
Elizabeth Dotson and Eun Jung Lee were both 5 and 4 winners in round three. They will face each other in the last quarterfinal match Friday morning. Both players won their second-round matches by identical 1-up scores.
Friday's play will have the quarterfinal matches in the morning with the semifinals in the afternoon. The event concludes with the 36-hole championship final on Saturday.
The U.S. Women's Amateur Public Links is one of 10 national championships for amateurs conducted annually by the USGA. The association also conducts the U.S. Open, U.S. Women's Open and the U.S. Senior Open.