I beat the top United States amateur, Leach said. Its overwhelming.
Leach of Louisville, Ky., earned a shot at Fowler by beating Scott Langley, 1-up earlier in the day.
I went out and stuck to my game, said Leach, a junior to be at Bellarmine University in Louisville. My putter was great and I made a lot of putts.
Leach said the key putt came at No. 13 when he hit a 10-footer for bogey to win the hole. Fowler missed an 8-foot bogey putt.
I expect myself to win everything, said Fowler, who plays for Oklahoma State. So its a letdown when I lose or get second.
In the morning, Fowler didnt play his best, but still defeated last years runner-up, Cody Paladino, 4 and 3. Fowler was 1-up at the turn, and won the 11th hole with a par and birdied the 12th with a short putt.
I felt like Im getting my game together, Fowler said. I had a few mistakes in the first two matches, but started playing well at the end.
Corey Nagy, seeded fifth, from Charlotte, was the only top-seeded golfer to advance to the quarterfinals. Nagy defeated Grant Leaver of Centerville. Tenn., 2 and 1.
Tenth-seed Andy Winings, from Brownsburg, Ind., missed making the quarterfinals, losing 3 and 2 to David Johnson of Palm Bay, Fla., in a third-round match.
The other quarterfinalists are Cason Hammock, Columbus, Ga.; Randall Hutchison, Traverse City, Mich.; Jack Newman, Des Moines, Iowa; Jeff Dennis, Jacksonville, Fla.; and John Chin, Temecula, Calif.
Two top 10-seeded golfers were eliminated in second-round matches. Fourth seed Brian Locke, Los Angeles, lost 2 and 1 to Kelly Kretz, Antigo, Wis.., and David Johnson beat No. 7 Jon McLean, Weston, Fla., 1-up.
Brady Johnson, Mill Bay, British Columbia, was beaten 3 and 2 by Hammock in a morning match. The loss came a day after Johnson had knocked out medalist Aaron Goldberg.