Denny McCarthy has taken down a giant in the U.S. Junior Amateur, defeating medalist Curtis Thompson in the round of 32 at Egypt Valley Country Club in Ada, Mich.

McCarthy, a senior this fall at Georgetown Prep, won 3 and 2. Thompson, playing in the event for the fourth time, is the brother of teenage phenom Alexis Thompson, the 2008 U.S. Girls Junior Amateur champion.

The 17-year-old McCarthy, a member at Argyle Country Club, took the lead with a birdie at the first hole and never gave it up. He currently trails Devon Purser, 1 down, through six holes of the round of 16.

Two other Washington area players also advanced Thursday morning. Ben Warnquist of Rockville defeated Bryson Dechambeau of Clovis, Calif., 3 and 2, but trails Richard Jung of Canada in the afternoon round, 3 down, through five holes. Haymarket’s Andrew Lister blew a 3 up lead on the back nine, but still won on the 21^st hole, making a birdie at the 558-yard par 5 to subdue Stephen Behr of Florence, S.C. In the afternoon, Lister plays Robby Shelton of Wilmer, Ala.