- Golfweek photo by Tracy Wilcox

David Chung vs. Byeong-Hun An: 8:30am PT.

David Chung defeated Scott Langley, 1 up,. Chung was 1 down after 11 holes, but birdied No. 12 and 15 to gain a 2-up lead. After Langely birded the par-3 17th to take the match the 18th hole. Chung, No. 4 in the Golfweek/amateurgolf.com Player Rankings, layed up on the 605-yard par 5 and made his birdie putt to close the match. Earlier this summer, Chung won the Western Amateur and Porter Cup. Langely won the 2010 NCAA Championship.

Byeong-Hun An defeated Max Homa, 1 up. An, the defending U.S. Amateur champion, never trailed in his match against his Cal Berkeley college teammate. He was 3 up through 12 holes and made par at No. 18 to win the match. An is attempting to become the first player to successfully defend his U.S. Amateur title since Tiger Woods won three in a row (1994-96).

• • • 

Patrick Cantlay vs. Peter Uihlein: 8:45 a.m. PT

Patrick Cantlay defeated Jed Dirksen, 20 holes. Cantlay was 1 down going to the 18th hole, but Dirksen bogeyed and lost the hole. After halving the 19th hole with pars, Cantlay made par on the 20th hole to win the match. Cantlay, who failed to advance to match play at the 2009 U.S. Amateur, is a freshman at UCLA.

Peter Uihlein defeated Morgan Hoffmann, 1 up. In a battle of Oklahoma State teammates, Hoffmann held a 1-up lead after eight holes, but couldn’t take control of the match. Uihlein squared the match with a par at No. 9 and took a 1-up lead for good with a birdie on the par-4 16th. Uihlein, No. 2 in the Golfweek/amateurgolf.com Player Rankings, advanced to the quarterfinals of the 2009 U.S. Amateur.