Usain Bolt had no doubts when naming his 'hardest opponent' in legendary career

Usain Bolt had no doubts in naming his toughest race and opponent during his illustrious sprinting career.

Bolt won eight gold medals across the 100m, 200m and relays, and holds two world and Olympic records in the aforementioned distances.

The Jamaican also ran over as far as 400m at junior level, but focused on shorter distances as he turned professional.

Throughout his career, Bolt defeated all of his adversaries, with the 100m competition at Beijing 2008 billed as a potential three-way fight between himself, Jamaica team-mate Asafa Powell and United States star Tyson Gay.

While that didn't exactly transpire - Gay failed to make the final, and Powell only ran a time of 9.95 to finish fifth - Bolt sprinted home to post a then-world record time of 9.69.

Bolt would smash that record a year later at the World Athletics Championships in Berlin, clocking a staggering time of 9.58.

The Jamaican couldn't beat that record throughout the rest of his career - and nobody else has beaten it either.

In 2015, two years before he retired, Bolt won the 100m final at the World Athletics Championships with a time of 9.79.

His main rival was the US sprinter Justin Gatlin, who received a four-year doping ban in 2006.

Upon his return, Gatlin consistently clocked times around 9.80 and won bronze in London 2012 behind Bolt and Yohan Blake.

Justin Gatlin and Usain Bolt pose with their medals at the 2015 World Athletics Championships - Getty

By 2015, the 33-year-old was in the midst of enjoying his fastest ever season by the time the Championships came around.

And he finished just a hundredth behind Bolt in Beijing and had to settle for silver.

Afterwards, Bolt described it as his 'hardest race' after battling back from injury.

He said: "Coming back from injury I've had a lot of doubters, it's been tough.

"For me to come to the championships and defend my title is a good feeling.

"I definitely think this was my hardest race. I've been through a lot this season."

While Gatlin was always a controversial figure in athletics as a result of his doping ban, he was the fastest man on the planet for three consecutive years between 2014 and 2016. He would beat Bolt, who won the bronze medal, at the 2017 World Championships.

He was still running under 10 seconds at the age of 39, when he failed to qualify for the Tokyo Olympics.