Dressel won the men’s 100 meter butterfly semifinal with a time of 49.50 seconds, which is a new world record in the event. He bested Michael Phelps’ previous world record of 49.82 seconds that was set back in the summer of 2009.
Fellow American swimmer Jack Conger finished the men’s 100 meter butterfly in sixth place with a time of 51.91 seconds.
This marked the second time that a world record by Michael Phelps was smashed at the FINA World Championships in Gwangju. 19-year-old Hungarian swimmer Kristof Milak also smashed Phelps’ world record in the men’s 200 meter butterfly.
A 22-year-old swimmer, Dressel won gold medals in the men’s 50 meter butterfly, where he had set a championship record and an American record, and he won the gold medal in the 100 meter freestyle with yet another American record. Dressel and Team USA also won the first gold medal in these World Championships in the 4×100 meter freestyle relay on July 21.
