Horsfield defeated No. 49 Doc Redman by a comfortable 5&4 tally.

The match was all-square until Horsfield won the 5th and 6th holes to take a 2 up lead. The Florida sophomore then kept the peddle to the mettle with wins on Nos. 9, 11 and 12. Horsfield was able to pull away in large part because of a front nine 29.

There were a handful of other upsets Thursday morning including two-seed Dawson Armstrong who lost 4&3 to No. 31 Jonah Texeira of USC. Texeira won four of the first eight holes in the match and was able to sustain a comfortable lead throughout the remainder of the match.

Five-seed Davis Riley was among the top-seeds to fall as well. Riley, a sophomore at Alabama dropped his match to No. 28 Curtis Luck of Australia. Luck ran away with he match late winning four straight holes after the match was all-square through 12-holes.

Among the other notable players to lose Thursday morning was reigning British Amateur winner, nine- seed Scott Gregory who was outlasted in 19 holes by No. 41 Nick Carlson of the University of Michigan.

After the match Carlson took about his winning birdie, "I was just trying to stay calm on the tee because I knew what it meant. I hit a really, really good drive and got a good kick left that gave me a little bit of a better angle [into the green]. I drew a good lie and had 115, which was the perfect number for a little sand wedge. We’ve been working on it all week and I just executed it to about 5 feet.”

The match of the morning went to No. 44 Cameron Young who bested 12-seed Stephen Franken in 23 holes. On the 18th hole Franken, an sophomore at NC State, was able to tie the match after neither player had led by more than one hole all day. Despite dropping the 18th hole Young, a sophomore at Wake Forest, was able to recover and win the match on the fifth extra hole.

A pair of AmateurGolf.com members, California teammates KK Limbhasut and Collin Morikawa, have punched their tickets into the Round of 16.

Limbhasut, the eighth and highest seed remaining, won 4&3 against Cristobal Del Solar to advance. Wins on the 10th, 12th and 14th holes turned a tight match into a late runaway.

“I like this course a lot because you have to hit the fairways in order to hit the greens," Limbhasut said of Oakland Hills Country Club. "The rough is pretty severe and it’s hard to hold the green with a shot from the rough.”

Playing as the 14-seed Morikawa easily handled Texas star Doug Ghim 5&4. Morikawa won five of the first eight to surge ahead early.

No. 62 David Boote is the lowest seed remaining in the field after his 3&1 win against 35-seed Ben Schlottman. Boote turned the tide of an all-square match after the 13th by winning Nos. 14, 16 and 17.