LONDON • Justin Gatlin has become increasingly irritated at being labelled the dope cheat, contrasting with Usain Bolt's superhero image in the sprinting world. But he can set that aside and spoil the latter's farewell at the world athletics championships.

The 35-year-old American - who last year became the oldest man to win a 100m Olympic medal when he took silver behind his nemesis Bolt - gets one last go at the Jamaican legend when the world championships get under way in London tomorrow.

It will be asking a lot of Gatlin - who served a four-year ban for doping from 2006 to 2010 - to achieve that. He has beaten Bolt, 30, only once in nine previous meetings over 100m, and that was four years ago in Rome.

However, there exists a mutual respect between the two old rivals.

"Away from the track, he's a great guy, he's a cool guy, there is no rivalry between us," said Gatlin.

"There is no bad blood. I'm a competitor, he's a competitor and he has pushed me to be the athlete that I am today."

Gatlin, one of the most tested athletes in sport since his return from the ban, showed his class in adding Olympic bronze (2012) and silver in the 100m to go with the gold he won in the pre-Bolt era in Athens in 2004. In addition, he also took bronze in the 200m in Greece.

He has the full house of Olympic 100m medals, plus a plethora of world medals including the 100m and 200m golds from 2005. But whether it measures up to what he could have won, had he not fallen foul of the dope testers, is a moot point.

The four years in the wilderness saw him try and fail three times to make it with a National Football League (NFL) team. Having lost his lucrative sponsorship deals, he had to sell his house and live in more spartan surroundings.

On his return to the track, there was a lot of anger stored up and Gatlin admitted that he "didn't like who I had become".

Intense chats with a priest brought peace and seemingly resolved that issue, but it has not lessened his hunger for success on the track.

Although he has hinted he might try and make the Tokyo Olympics in 2020, realistically, London may represent the last chance to be a genuine contender at a major championships - and deliver a title for his seven-year-old son Jace.

"I mean, if anything, it makes me nervous. Your son telling you, 'you better win'," he said.

"That's why I'm here, I'm trying. But if my son says that, I will try to move mountains."

AGENCE FRANCE-PRESSE