If anybody can spoil the Usain Bolt–Justin Gatlin showdown at the World Championships in August, it may be a Canadian who was 9 years old when Bolt and Gatlin debuted at the Olympics.
http://olympictalk.nbcsports.com/2015/06/19/andre-de-grasse-track-and-field-canada-usain-bolt-justin-gatlin/
http://olympictalk.nbcsports.com/2015/06/19/andre-de-grasse-track-and-field-canada-usain-bolt-justin-gatlin/