LOS ANGELES - Doug Ghim advanced to the semifinals of the U.S. Amateur on Friday with a 2-and-1 victory over Scotland's Connor Syme.
Tommy Humphrey also advanced with a 1-up victory over Taiwan's Chun An Yu. Doc Redman beat Australia's Travis Smyth 1 up, and Mark Lawrence Jr. finished off Dawson Armstrong 3 and 2 to complete an all-American final four at Riviera Country Club.
Humphrey, who plays at Vanderbilt, could be playing his way into a spot on the U.S. Walker Cup team in three weeks with an impressive week at the Amateur. He advanced by rallying to take the lead on the back nine before holding off a strong challenge from Yu, an Arizona State sophomore.
Ghim, the reigning Big 12 Player of the Year at Texas, never trailed in his match with Syme, who had been on a strong run. Ghim took charge when he bogeyed the 16th, yet still won the hole when Syme double-bogeyed it.
''This golf course is so demanding, and the conditions are getting harder every day,'' Ghim said. ''You just can't slip up, because you know once you do, your opponent is going to take advantage of it. There are nerves for sure, but everyone is feeling them. I'm more than happy to feel those nerves, because that means I'm doing something right.''
Redman, a 19-year-old from Clemson, trailed Smyth by two holes with six to go, but Redman rallied and finally advanced when his Australian opponent bogeyed the 18th. Smyth had reached the quarterfinals by knocking off No. 3-ranked Braden Thornberry and 12th-ranked Will Zalatoris in back-to-back matches Thursday.
Lawrence, who plays at Virginia Tech, had the smoothest quarterfinal victory, winning four of seven holes after the turn to finish off Armstrong.
Ghim will face Humphrey, while Redman will meet Lawrence in match play Saturday.