But recent injury problems and the form of world 100m champion Yohan Blake - who beat Bolt over both 100m and 200m at the Jamaican Olympic trials - and also America's Tyson Gay mean the competition is now much fierce than had been expected.
'This is the most exciting 100m final we’ll ever see,' Black told Metro.
'It's fabulous what’s happened with Bolt - it's not a surprise to those of us who follow the sport, because no matter how good you are, if you’re not on top of your game there are people behind him who can challenge you.
'Clearly Bolt's got a few problems - four years ago he had 10% on the rest of the world, now it’s down to about 5%, and if it dips less than 5% he’ll really be pushed.'
Black was speaking at the Nature Valley Games at London's Honorable Artillery Company headquarters, where he and fellow Atlanta 1996 4x400m relay silver medallist Jamie Baulch took part in games like hay bale hurdling and a tractor race, bringing a bit of the country to the city.
