Slow start was Bolt's undoing

It wasn't supposed to end this way. Usain Bolt, multiple world-record holder and gold-medal winner, was meant to sail through to the finish line ahead of every one else, lit up by 80000 flashes capturing the moment. But it was not to be as the world's most-decorated sprinter failed to win his final individual race.

He was beaten, not by one man, but by two. Not by any man, but by his long-time rival Justin Gatlin. Second to Bolt in 2013, 2015 and 2016, Gatlin finally, at his final opportunity, reversed the order.

Bolt took this final defeat in his stride, doing a celebratory lap as though he had won the title. Gatlin and Christian Coleman, who came second, did theirs, but they'll be lucky to feature as "incidental" background in most people's photographs of the night. It was all eyes on Bolt, as it has been since Beijing 2008, but it is unlikely to be so from now on.

The numbers tell the story of the race. The first key element of a good 100m race is how fast the sprinter reacts to the gun. The legal limit is 0.1 seconds - any faster, and you're disqualified, as happened to South Africa's Thando Roto in round one. Any slower, and you're playing catch up.

Bolt's reaction time on Saturday night was 0.182s. That's abysmally slow. Compare it with Coleman's 0.123s and Gatlin's 0.138s. The difference between Bolt and those two? 0.059s and 0.044s respectively.

Now consider that their finishing times were 9.92sec, 9.94 and 9.95. Bolt, in other words, was beaten by 0.03sec and 0.01sec. He gave up 0.04sec before he'd even taken a step, the entire margin of defeat being covered by the time it took him to react to the gun.

It has been this way for Bolt for a while. Back in 2009, when he set the current world record, his reaction time was the second fastest in the race - 0.135s. He got to 20m first. In London on Saturday, he was trailing near the back.

Even his high top-end speed could not make up for that first 40m - Bolt Version 2009 would still have won Saturday's race even with such a slow start. That Bolt, however, no longer exists, and strain and try as he might, the Americans remained clear.

Bolt, then, exits stage right, though we will still see him in the relays, where he may be able to close out his career with gold. That will be a challenge, given the US's relatively faster individuals, plus challenges from the UK and possibly South Africa, if our team management can get into gear.

What remains behind is Justin Gatlin. World Champion. Twice-convicted doper. And recipient of loud booing in London, before the race and when the result was put up on the giant screens.

Gatlin is the pantomime villain of track and field. That's what two bans will get you. No matter that five out of seven of Bolt's rivals in the London 2012 Olympics have also been banned for doping. No matter that suspicion rightly exists around every sprinter, including Bolt.

Bolt, supposedly, saved the sport. Steve Cram, one of many sycophantic cheerleaders who finds himself watching the sport from behind a microphone, actually called the Bolt vs Gatlin duel of 2015 a "battle of good vs evil", and when Bolt won, proclaimed: "Usain Bolt has saved athletics." Embarrassing, but not unique.

On Saturday night, commentators were crying as Bolt did his farewell lap. The problem with that is this: Bolt's presence has allowed the sport to pretend things are different. He was the sport's safe space.

His departure, to be replaced by Gatlin, even if only for a year (Gatlin is 35 and surely near retirement), is perhaps the most appropriate conclusion to this instalment of track and field's clearly troubled history.

So far in London, track gold medals have been won by a man who has two coaches under police/FBI/anti-doping investigation, a woman who is never tested in the isolation of Ethiopia (and one many seriously doubt), and a twice-convicted doper.

Like Gotham City and Batman, track and field gets the heroes it deserves, but not the ones it needs.