He finished the tournament at 19-under par, two strokes ahead of Collin Morikawa and Cameron Young.
Niemann was the number one ranked golfer in the World Amateur Golf Ranking for 44 weeks, from May 2017 to April 2018, when he turned professional.
Niemann won the 2017 Mark H. McCormack Medal for being the top-ranked player in the World Amateur Golf Ranking at the conclusion of the summer's championship season, thus gaining entry into the 2018 U.S.
Open and into the 2018 Open Championship. He won the 2018 Latin America Amateur Championship gaining entry also into the 2018 Masters Tournament.