London: Justin Gatlin's win in the 100 metres at the World Athletics Championships was "not the perfect script", IAAF President Sebastian Coe said on Sunday.
American Gatlin, who has served two suspensions for doping offences, ruined Usain Bolt's fairytale farewell on Saturday by beating the Jamaican sprint great in his final ever individual race.
Bolt came third, behind 21-year-old American Christian Coleman, whose compatriot Gatlin was booed by the crowd for his win inside the London Stadium.
"I'm not eulogistic that someone who has served two bans has walked off with one of our glittering prizes. But he is eligible to be here," Coe, the head of the sport's governing body, told the BBC.
"It's not the perfect script. I thought Usain was very generous with the observations he made. That must have been a bitter event for him to swallow. He was bigger than the moment and it typifies his career."
Coe reiterated his support for life bans for convicted drug cheats after Jamaica's prime minister Andrew Holness said he wanted the measure introduced to fully eradicate cheating.