Sung Hyun Park capitalized on the favorable morning scoring conditions, shooting a 6-under par 72 Friday to take the early clubhouse lead after the second round of the U.S. Women's Open.

Park came from South Korea to her first U.S. Open mostly for the experience but now heads into the weekend in contention in just her fourth LPGA tournament of the year.

Amy Yang shot a 71 and finished the second round two shots back. World No. 1 Lydia Ko bounced back from a 1-over par first round to shoot 66 and stands three shots behind.

First-round leader Mirim Lee, who tied a U.S. Open record with an 8-under par on Thursday, teed off in the afternoon on Friday.