London - Usain Bolt was left ruing a disastrous start as his failure to fire saw American arch-rival Justin Gatlin poop what was supposed to be a party in his final 100m race at the world championships on Saturday.
"My start is killing me," said Bolt, who battled back up through the field to claim bronze behind Gatlin and silver medallist Christian Coleman.
"Normally it gets better during the rounds, but it didn't come together. And that is what killed me. I felt it was there."
Gatlin, who has served two doping bans, shrugged off the boos of the crowd to hail the great Jamaican, even dropping to his knees to bow to his rival.
Gatlin said Bolt had told him "You don't deserve all these boos."
"So I think for all that and inspiring throughout my career he's an amazing man."
Bolt had complained about the starting blocks in Friday's first round, and left himself too much to do after finding himself behind Coleman.
"It was rough," he said. "I was a little bit stressed. But I came out like at any other championships and I did my best. Thanks for the support. I could never expect this from any other crowd. They are what pushed me to do my best.
"The atmosphere was wonderful. I knew they would come out. I'm just disappointed I couldn't do better for them but that's how it goes sometimes."
Gatlin was loudly jeered by the sell-out 60,000 crowd at the London Stadium, where Bolt's victory over him at the 2012 Olympics was hailed as triumph of 'good over evil' given the American's doping-tainted past.
"It's just so surreal right now -- I jumped in the crowd and went wild," said the 35-year-old who has served two doping bans, the second between 2006-10, a period of forced exile that he credits has helped his track longevity.
"Usain has accomplished so much in our sport and inspired others like Coleman to come out and compete in the championships.
"Usain said: 'Congratulations, you deserve it.' And that's from the man himself. He knows how hard I work. Tonight was all about the W (win) and I managed to sneak it."
Gatlin played down the jeering, perhaps summing up the difference between him and Bolt perfectly by saying: "It's not about the crowd: I tuned it out through the rounds and stayed the course. I kept my energy through the semis and came to the final to do what I do.
"The people who love me, they're cheering for me. They're at home cheering for me and my coaching manager is cheering for me, and that's what I've been focusing on.
"I thought of all the things I would do if I won, and I didn't do any of that. It was almost like 2004 all over again" when he won the Olympic 100m title before going on to claim a world sprint double in 2005 and then falling foul of doping laws.