It requires something of a leap of faith to believe Dawn Approach can win this afternoon's Epsom Derby but if the Irish star pulls it off, then racing romance will have triumphed over scientific reason on the most important Classic day of all.

Unbeaten in seven career starts, including a brilliant 2,000 Guineas triumph over a mile at Newmarket a month ago, Dawn Approach is almost universally acknowledged as the most talented runner among the dozen lining up for the world’s most famous Classic.

That seven of them are Irish means the odds on a 17th win for this country in a race that has defined the global breed are almost as short as those on the over-employment of the “if-he-stays-he-wins” cliche before 4pm.

Guineas heroes
Not that the well-worn phrase isn't true: if Dawn Approach does stay, he probably will win. But history is littered with the dented reputations of brilliantly fast two-year-old champions and Guineas heroes who have failed to extend their brilliance to a mile and a half.

Nijinsky in 1970 is the last to have boasted Dawn Approach’s precocious juvenile profile and still triumphed around Epsom’s roller-coaster test.

That legendary horse was a freakish talent, and Dawn Approach is going to have to be a genetic freak to overcome everything that’s against him.

The Derby lead-up has been full of the findings of an Irish genetics company, Equinome, which divides thoroughbreds into three genetic types and whose categorisation of Dawn Approach theoretically means he has as much chance of staying a mile and a half as Richard Dawkins has of delivering an Easter blessing.

That the colt is trained by Jim Bolger, a director of the company, gives a fascinating "nature v nurture" frisson to Derby 2013, because Bolger's unique position in world racing right now as a top trainer and breeder is validation of an unshakeable faith in backing his own judgement.

And despite the cold, scientific evidence presented to him by his own company, Bolger is still defiantly backing his hunch that Dawn Approach can stay the Derby trip.

“If you were to take it at face value, he probably would not get a mile and a half, but he settles so well, and has such a good temperament, and he has so much class, he may well get a mile and a half,” the legendary trainer, who trained Dawn Approach’s sire, New Approach to win five years ago, said yesterday.

“But we won’t be sure until we try.”

Pecking order
That is the allure of the Derby, never the final-step in establishing the Classic pecking order, but over 233 years always the most important one. By 4.05, we will know if Dawn Approach is a potential great in the mould of Nijinsky, Sea The Stars and Frankel, or a brilliant miler whose talent couldn't out-perform his genetics.

If it is the latter, Aidan O’Brien looks to have the most obvious ammunition to step into the breach with five hopefuls headed by Battle Of Marengo, the pick of his son Joseph.

But finding one of those rare super-champions that come to define the sport is always the most exciting prospect of all. Dawn Approach has the chance to fill such a role.

It surely isn’t just romantics who will yearn for him step up.