An attritional run-in has resulted in an Epsom Derby shape that would have seemed unlikely at the start of the season but which could provide Frankie Dettori with racing's ultimate redemption in the sport's greatest classic prize on board the favourite Golden Horn.

Unlike in New York at almost midnight tonight, when the outstanding American Pharoah attempts to clean-sweep the US Triple Crown for the first time in 37 years in the Belmont Stakes, the 2015 Derby has a comparative survival-of-the-fittest feel.

The injury sustained earlier this week which prevents Zawraq lining up is just the latest setback. Aidan O'Brien is chasing four in a row in the Derby, and a sixth victory overall to emulate his legendary Ballydoyle predecessor, Vincent O'Brien, but those who reckoned Giovanni Canaletto would lead his assault today would have been in a minority.

However as John F Kennedy and Ol’ Man River flopped, it is the brother to the 2013 winner Ruler Of The World that heads a Ballydoyle trio and he has been the big ante-post gamble too despite getting beaten by a filly on his only start this season just 13 days ago.

Raw colt

Giovanni Canaletto still looked desperately inexperienced on that occasion and O’Brien initially seemed to downplay Epsom as a target.

Yet here he is with Ryan Moore on board and since O'Brien got Ruler Of The World from a maiden to Derby glory in just 40 days, no one will entirely dismiss Giovanni Canaletto's chances.

Ken Condon and Pat Shanahan are two other Irish trainers taking their shot at Derby glory. Shanahan's Carbon Dating looks a no-hoper. In contrast Condon's Success Days boasts credentials in a Ballysax-Derrinstown double that would have him near the top of the betting if O'Brien trained him.

Both Condon and jockey Shane Foley are experiencing the Derby for the first time on a colt who was supplemented into the race at a cost of over €100,000 but who is unproven on ground that is likely to dry up significantly.

Of the two proven Group One winners in the field, the French-trained Epicuris is at Epsom purely because his issues with the stalls ruled out last Sunday’s French Derby while potentially Elm Park looks a type to struggle on the course.

In fact Qatar Racing's other hope, the German-trained Rogue Runner could reward big-priced each-way punters. He was beaten in a bog last time but will relish better ground and it is significant he appears at all since trainer Andreas Wohler has a global reputation.

But almost by process of elimination it is hard to escape Golden Horn’s claims in the most coveted Derby. His Dante win is the outstanding piece of form in this field, his stamina claims on balance look sound and conditions should favour him.

He also has Dettori. The Italian is having his 20th Derby ride. His sole previous win came on Authorized in 2007 but he hasn’t ridden the race since 2011. Since then he has served a six-month ban for cocaine-use and endured fluctuating fortunes such as losing the ride on the Arc winner Treve.

So if Authorized was sweet, Golden Horn could be the sweetest of all.