The upstart junior, who won the European U23 Championship and the Oslo Diamond League titles earlier this summer, took control of the race immediately and held his lead to cross the line first in 48.35, the second-fastest time of his young career. Clement, who actually had the fastest reaction time today at 0.153, had to settle for bronze in 48.52 as Yasmani Copello of Turkey edged him for silver in 48.49.
The 31-year-old Clement won world titles in the event in 2007 and 2009.
Warholm's win is even more impressive considering that he is a former decathlete, having won silver in the event at the 2015 European Junior Championships as well as gold in the octathlon at the 2013 World Youth Championships. He has only focused on the 400m hurdles for the past two years.