Usain Bolt says he is not invincible as he prepares to face his biggest rivals over 200m in the latest Diamond League meeting in Paris on Saturday.
The six-time Olympic gold medallist will go up against his fellow Jamaican Warren Weir and the fastest man in the world this year, American Tyson Gay.
"I never said I was invincible," admitted 26-year-old Bolt.
He went on to say that a win in Paris would give him a boost ahead of next month's World Championships in Moscow.
"When I'm in great shape and I'm at the top of my game, I'm very confident that no-one can beat me because I know what I'm capable of," said Bolt.
"But you can be beaten. There's times when you get injuries, there's times when you're off your game. There's so many different scenarios that can happen."
The men's 400m sees a clash between the last two Olympic champions, LaShawn Merritt of the United States, and Grenada's Kirani James.
In the women's 100m, American double Olympic champion Shelly-Ann Fraser-Pryce faces Trinidad and Tobago's Kelly-Ann Baptiste, who has been the fastest woman in the world this year.