American Freddie Crittenden used the newly introduced repechage to his advantage on Tuesday as he reached the 110 metres hurdles semifinals after jogging through the opening round with an injury.
Athletes have celebrated the addition of the repechage round in Paris and Crittenden may be its biggest proponent after he moved tentatively through his first heat in 18.27 seconds on Sunday with an aggravated adductor muscle.
The strategy gave Crittenden, who finished second at the US trials, two days to address the issue and he looked to be in good enough shape as booked a spot in Wednesday's semifinal in 13.42.
Spain's Asier Martinez finished four hundredths of a second slower and will also advance.
Repechage - which translates from French to "fish out" or "to rescue" - allows competitors who do not initially clinch spots in the semis to race again with a chance of moving on.
Kazakhstan's David Yefremov was disqualified for a false start in the second heat and officials had to reset the athletes at the start on multiple occasions to groans from the crowd at the Stade de France.
Fans' frustration turned to joy, however, as home hope Raphael Mohamed (13.54) finished second behind Brazilian Rafael Pereira (13.54), booking his spot in the semifinals by one thousandth of a second.
China's Qin Weibo (13.44) won the third heat with France's Wilhem Belocian (13.45) also moving on.