Rio Olympics 2016: Usain Bolt calls for faith but questions if rivals are drug free
Usain Bolt has defended athletics at a news conference that featured a dance troupe and a rapping Norwegian.
Amid the razzamatazz, the six-time Olympic champion, 29, made a serious point about the future of the sport.
The run-up to the Games was dominated by Russia's doping scandal, while American rivals Justin Gatlin and LaShawn Merritt have served drug bans.
"People should have faith," said Bolt. "We're weeding out the bad ones. We're going in the right direction."
But the Jamaican added "nothing is guaranteed" when asked whether the sprint races at the Games, which start on Saturday, would be drug-free.
Bolt, who said in February he would retire from athletics after the 2017 World Championships, confirmed this would be his last Olympics.
The sprinter, who holds the 100m and 200m world records, also said he was aiming to become the first man to run under 19 seconds in the 200m.
He could leave Rio with a third successive Olympic treble after winning the 100m, 200m and 4x100m relay titles in 2008 and 2012.
"The 100m is never stressful," Bolt said. "For some reason, when I get to the 200m, I'm always a little bit nervous."
Johnson v Bolt
Retired USA sprinter Michael Johnson believes he would have beaten Bolt at 200m if they had raced in the same era.
The 48-year-old ran a world record 19.32 seconds to win 200m gold at the 1996 Games in Atlanta.
Bolt lowered Johnson's world record twice, setting the current standard of 19.19secs at the 2009 World Championships in Berlin.
Yet Johnson told the Radio Times: "I'd have been first."
Johnson, working in RIo as a pundit for BBC Sport, thinks a rivalry between himself and Bolt would have seen one of them break the 19-second barrier.
"He thinks the time would have been 19.01 or 19.02," the American said. "I think we would have been around 18.99, so we differ on that."
"But we both agree that we each would have won!"
The athletics events in Rio begin on Friday, with Bolt first in action in the 100m on the Saturday, before the final on Sunday.
Box-office Bolt takes centre stage
Bolt's news conference on Monday was held at the Cidade das Artes, the home of the Brazilian Symphony Orchestra and the largest theatre in South America.
The world's media queued for more than two hours before the start.
When the event did get under way, there were fewer empty seats than at many of the actual events.
Given the significant media appeal of the world's fastest man, it was perhaps to be expected that the news conference would be far from ordinary.
A Norwegian journalist declined to ask a question, instead proclaiming his love for Bolt before rapping a song in his honour and then blowing him kisses while samba dancers joined the sprinter on stage and danced with him.
"I like to entertain, because that's what people come out to see," said Bolt. "I try to entertain and make it different. That's my personality."