Justin Gatlin upset Usain Bolt to claim the 100 metres title at the World Championships on Saturday but was mercilessly booed during the competition.
The American has served two bans for doping violations but has returned twice and, here, we look at the issues surrounding the race.
Why was Gatlin booed?
Gatlin has always denied being a two-time drug cheat.
He was first banned in 2001 for two years for traces of an amphetamine contained in medication he had been taking since he was young for attention deficit disorder. The ban was later reduced to one year and he returned to win the 100m title at the 2004 Olympics and also claimed the 100m and 200m world titles in 2005.
Gatlin also served a four-year ban from 2006 - reduced from eight after he co-operated with US authorities over doping - for testing positive for testosterone.
Again he denied doping, insisting the positive result came from a therapist rubbing testosterone cream on him - a claim the therapist has refuted.
Is it fair?
A complex issue and the singling out of Gatlin is debatable. Over 25 athletes, including Gatlin, competing at London 2017 have been sanctioned for doping violations.
Yohan Blake, who was also in the final and Bolt's training partner, was banned for three months after testing positive for methylxanthine - a substance not on WADA's banned list at the time - in 2009 but was cheered during the 100m.
It is a global issue, rather than individually down to Gatlin - who has been singled out at the championships, prompting his father to criticise the coverage his son has received.
Officially he broke the rules, even if a panel hearing into his first positive test conceded he did not intend to cheat, but it is not as black and white as the boos suggest.
Has it tarnished the championships?
It is the talking point of London 2017 and fans are certainly more cynical after the Russian doping scandal.
Lord Seb Coe said before the championships that doping was not the sport's biggest challenge - rather it was attracting the new generation to it - but the focus on Gatlin and the issue of doping puts his comments in sharp focus.
Trust in athletics has been eroded and suspicion is even cast on clean athletes.
Gatlin's victory raises the important point of lifetime bans for dopers but while the IAAF, athletics' governing body, allows him to compete the talking point will remain.
What went wrong for Bolt?
The Jamaican refused to blame the blocks after the final but he clearly struggled with his starts, having criticised the blocks after the 100m heats on Friday.
He said: "That was very bad. I stumbled a little bit coming out of the blocks. I am not really fond of these blocks. I think these are the worst blocks I've ever experienced."
His training was disrupted this year after the death of close friend Germaine Mason and Bolt conceded he was not in the type of shape he would have liked.
Bolt was full of bravado last week before the championships, saying he would not lose, but it was just the mind games starting early.
What next for Bolt?
The eight-time Olympic champion will bow out after the 4x100m relay on Saturday, bringing the end to a glittering career.
It will be his final chance for a golden retirement after Saturday's 100m did not go to plan and he finished third behind American's Gatlin and Christian Coleman.
Bolt usually runs the final, anchor, leg so will at least avoid a problem with the blocks which he struggled with throughout the 100m. His start ultimately cost him victory.
After the weekend, the 30-year-old admits he does not know what he will do - except enjoy not getting up for training.