Rio Olympics 2016: Usain Bolt wins 100 metres final to become first sprinter to take the title three times

USAIN BOLT. About the only thing that can bring Rio to a standstill, except the traffic.

Last night he kicked off his bid for the Olympic triple-triple when he clocked 9.81secs - his fastest time this year - to clinch his third 100m crown.

He held off the threat of Justin Gatlin who had to settle for silver again in 9.89secs and Canadian Andre de Grasse, who took bronze in 9.91secs

Only one man could have really stood between Bolt and history and that was Gatlin.

The two-time drug cheat who Bolt famously beat to the 100m, 200m and 4x100m world crowns last summer.

Once again Bolt had been cast as the saviour of the sport ahead of last night's showdown with American Gatlin the villain amidst a possible nightmare scenario of a doper standing on top of the podium in a year when the sport has been rocked by the Russian drugs scandal.

Seb Coe, the president of the IAAf, the sport's governing body, had already said a year ago that prospect made him feel "queasy."

The contrast when they lined up on the track could not have been bigger.

'Bolt, Bolt' chanted the crowd - the biggest so far in the Olympic Stadium here - as the Jamaican got into the blocks while Gatlin was met with a barrage of boos.

So for Bolt a personal mission; for the sport a battle to salvage its doping-ravaged reputation.

Russian athletes kicked out of Rio because of evidence of Cold War style state-doping - but who have never tested positive themselves - had even pointed out the hypocrisy of Gatlin's mere presence here.

And fellow Team USA member - swimmer Lily King who won 100m breaststoke gold last week - had said he should have been banned for life.