"That is it", Bolt said.
The Ontario-born sprinter had run the fastest wind-assisted 100m of the year, a time of 9.69 seconds, in Stockholm in June.
Farah's haul of nine world and Olympic 5000m and 10,000m titles stacks up alongside that of the Jamaican and few would bet against Sir Mo doing the double again in his last major championships.
De Grasse is seen as a contender to take over Bolt's throne following his retirement and was also tipped to be a candidate to spoil the party on Saturday following his 200m silver, 100m bronze and 4x100m bronze at the Rio Olympics a year ago.
On Tuesday, the Jamaican had told reporters: "Wayde van Niekerk is proving he is a world star". And now the great track and field superstar is getting ready for his final hurrah as the World Athletics Championships kicks off in London on Friday.
The unknown quantity is 21-year-old US college student Coleman, who's comfortably the fastest in the world this year at 9.82 seconds but who still sounds a little starry-eyed about the prospect of beating Bolt, calling the idea "crazy".More news: President Donald Trump says he won't stay off social media
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The four years in the wilderness saw him try and fail three times to make it with an National Football League team, and having lost his lucrative sponsorship deals, he had to sell his house and live in more spartan surroundings. If it had gone the other way we wouldn't have just lost the Games, we wouldn't have had the Olympic Park or the stadium and wouldn't have been in a position to bid to stage a World Championships. At the age of 30, one knows that Bolt is not the youngest man in the sport.
"I'm not anxious. It's a championship, so it's about who can keep their nerve".
Jamaican athlete Usain Bolt has dominated the track events for almost a decade now, winning many medals and breaking more records. I know it's your last race we are going to miss you a lot on the track.
It looks likely to be the man who finished with silver at London 2012, Botswana's Nijel Amos, but it just might be Kenyan newcomer Emmanuel Korir, who set the world's best time of the year at 1:43.10.
France's 30-year-old world pole vault record holder Renaud Lavillenie will once again seek the only gold he is missing from his collection, but Sam Kendricks of the USA has cleared 6.00m this season and looks the favourite.