Usain Bolt edges Asafa Powell in Oslo (Mark Shearman) © Copyright
Until last summer Bolt was undisputed favourite to retain the title he won in Beijing where with a supercharged performance he lowered his own three month old World record from 9.72 to a fabulous time of 9.69.
There is no doubt it would have been even faster when holding a three metres lead he raised his arms and virtually shut down his huge 6ft 5in frame 20 metres from the line when winning ahead of Richard Thompson and Walter Dix.
However now there is a new kid on the block and an athlete he knows really well - his training partner Yohan Blake. His fellow Jamaican won the 2011 World Championships 100m dash when Bolt committed the cardinal sin of false starting, an error not expected of a man of his experience, and was disqualified.
Since that dark night for his teammate in Daegu Blake has progressed at a rapid rate of knots. Apart from being the world leader going into what is his Olympic debut he also got the better of the World record holder when pushing Bolt and Asafa Powell in an explosive race at their Olympic trials into the minor placings with that personal best time of 9.75.
Yet Bolt remains supremely confident he will be back in the best shape of his life which four years ago apart from his lightning 100m success also saw him also smash the 200m World record and then share another with Jamaica's 4x100m relay quartet.
Recently returned from German specialist Hans-Wilhelm Müller-Wohlfahrt who gave the green light regarding his fitness after problems with his right hamstring, the 25-year-old said: "I am definitely confident that I can do what I did (in Beijing).
"I got checked out and it's all right, I am happy with where it's at. I'm training hard and looking forward to the start of the Olympics."
Blake however sent out another late message that he will be bidding to take away Bolt's title. In his final outing before London "The Beast" as he is nicknamed because of his commitment to an ultra-strict training regime even on Christmas day, flew to the third fastest time of his career when winning in 9.85 seconds in Lucerne on 17 July.
While the pair are claiming the spotlight there are others who quite rightly believe they have the credentials to topple the two Jamaicans headed by the US pair of Justin Gatlin the 2004 gold medallist and Tyson Gay the 2007 World champion.
Former World record holder Powell although he still tends to be inconsistent at major championships when having to face three rounds before a final and Trinidad's Keston Bledman - Gay's training sidekick - will also expect to be in the mix.
Each and every one of them will vividly remember that the scenario can quickly change as happened in Daegu with Bolt's DQ which allowed Blake to dominate the race ahead of Dix and the ageless Kim Collins.
Gay is now clearly feeling fully fit after almost a year's absence, and with a hip operation requiring surgery, he believes he can be one of the main contenders when it takes place in London on 5 August. Of the field, he said: "There are a lot of people now in the 100m, it is open for the Games. Bolt, Blake, Gatlin, my training partner Bledman. It will be spectacular."
France's European champion Christophe Lemaitre isn't quite yet in the fast lane for a medal despite his potential for the future while newly crowned World Junior champion Adam Gemili even with home support may find it a bridge to far to reach the final at this stage of his career.
David Martin for the IAAF
1999 Upsets in Rio