WASHINGTON, USA (AFP) – Justin Gatlin, the 2004 Olympic 100-meter champion who missed the 2008 Olympics while serving a four-year doping ban, comes to the London Olympics with hopes of legitimising his tarnished legacy.

At age 30, Gatlin ran the fastest 100 of his career, 9.80 seconds, to win the US Olympic trials final. His time was .05 faster than his gold medal time at the 2004 Athens Olympics.

“I think there’s a lot left in the tank,”; Gatlin warns.

But restoring his reputation after his doping ban has been an even harder run that qualifying for the London Games.

“I’ve heard a lot of words over the past year or so — my road, redemption, my journey,” Gatlin said. “I was just sticking to what I know — being a fast runner, breaking it down to its simplest form and just competing. I have been through some dark past. What has kept me going is the faith of my fans knowing I am a legitimate athlete. I’ve been tested multiple times since I have been back. I’m a clean athlete. I’m focused on that.”

Gatlin has lived the golden dream and the doping nightmare and prefers to leave both behind him for now.

“I’ve no chip on my shoulder or vendetta. It’s not about judging myself,” Gatlin said. “Right now I’m focused on what’s in front of me.”

That is a showdown with reigning world champion Yohan Blake and reigning Olympic champion and world record-holder Usain Bolt.

“We all have our eyes on that prize we want to get at the end,” Gatlin said. “I don’t think I would come back to a sport where I’m OK getting second or third.”

Gatlin won 100 meters gold at Athens and 100 and 200 world titles in 2005, but he tested positive for doping and was banned from 2006-2010.

Critics say he should not even have a chance for another Olympic appearance after shaming the sport.

“There was a point in my life when I was torn up,”; Gatlin said. “That’s why I intend to show my detractors and naysayers that I am a legitimate athlete. I might not be one of the most charismatic guys out there, but I’m one of the bravest.”

Gatlin, who won the world 60m indoor crown earlier this year, said he felt excited like a child running at the trials and has learned from his banishment about how much he needed to mature in order to appreciate his achievements.

“I’m a little older but also a little wiser and a little grittier,” Gatlin said.

“I realised life is hard and something you work hard at. I know what it’s like to have a talent and not be able to use it and that makes me appreciate it even more.”

Gatlin joined forces last October with a coach who knows sprinting and falls from sporting grace, Dennis Mitchell, a 1992 100m Olympic bronze medalist who was hit with a two-year doping ban in 1998.

That has just put more of a spotlight upon Gatlin and his Olympic comeback, which has already been a triumph in some ways.

“People just want to see how far the ride takes me,” Gatlin said. “I don’t think anybody expected me to get this far. Just being able to come back and compete is a victory in itself.”