Ben Johnson - his achievements will always be tainted

The man who calls himself PhenoMOnon has medals galore - three World Championship 100m golds in a row, an Olympic title from Sydney, 200m gold from Seville two years ago and a clutch of relay golds that will probably be added to in a week's time.

Greene has also been at the top of the tree for longer than any of his predecessors. You don't expect sprinters to last for more than a couple of years at their peak.

Look back and you'll see what I mean. Donovan Bailey was the last man apart from Greene to take World gold, back in 1995.

The following year he added the Olympic title with a world record run in Atlanta, but by 1997 and the World Championships in Athens he had been overtaken, quite literally, by Greene.

Linford Christie was the same. Olympic champion in 1992, world champion in 1993, his star burned brightest for just two years.

The man who held the world record before Bailey, American Leroy Burrell, never won a major championship gold and can be removed from the equation without too much fuss.

We're left with just two names. One of them, still the most famous track and field star in Canada, even had the same bullish style as Greene.

But Ben Johnson's name - and his 1988 Olympic final time of 9.79secs, which matches the fastest time Greene has run - is forever discredited by his positive drug test in Seoul.

We come, inevitably, to Carl Lewis.

The man himself would tell you who was the greatest without a second thought, just as he did throughout his career.

Widest margin

He was also the world record holder, his run of 9.84secs in Tokyo in 1991 taking a huge four hundredths of a second of the old mark.

Then again, when Greene broke Bailey's old mark in 1997, he knocked five hundredths of a second off the record, the widest margin by which the world record had been broken since electronic timing was introduced in the 1960s.

Lewis' three world 100m titles could be said to be worth more than Greene's, because he won them in the days when world championships only came round every four years.

Except he wasn't the first man across the line on all three occasions.

The second crown from Rome in 1987, was only awarded retrospectively in 1992, when Ben Johnson finally admitted to have been using steroids the year before he was eventually caught.

Lewis has another 100m Olympic title on Greene. But with the Kansas Cannonball insisting he will be competing in Athens in 2004, who's to say that won't be matched?

Over 200m it's a different story. Although Greene took the 100m and 200m Worlds double in Seville two years ago, becoming the first man to do the sprint double in a major championship since Lewis at the Los Angeles Olympics in 1984, he's not a natural.

He's a 100m runner quick enough to win over the longer distance. Lewis' graceful style was, if anything, even more effective over 200m.

Who to chose? The tree trunk-legged Mo, who hammers towards the line like a balletic bulldozer, or the fluid Californian, who floated down the track like a leaf in the breeze?

Lewis could be rattled at the start of a race

I have them neck-and-neck by every measurement bar one, and that is mental strength.

Lewis, for all his talent, could be unsettled on the blocks and beaten. Witness his baffled expression when Johnson did him in 1987 and 1988, or when Christie out-psyched him in Gothenburg in 1993.

Greene just doesn't crack. While his principal rivals on Sunday were shaking on the blocks like schoolchildren, false-starting left, right and centre, Greene was unmoved.

He knew his knee wasn't right, he knew Tim Montgomery was going lightening fast and he knew Ato Bolden wanted revenge.

It didn't matter. He stayed strong and ran his race perfectly. Without the tendonitis, he would have buried his own world record.

He's the best, all right.