Royal Ascot winner Santiago heads Aidan O’Brien’s quest for a 14th success in the Dubai Duty Free Irish Derby at the Curragh on Saturday.

The Authorized colt finished second on his first two starts as a juvenile — including to top-class filly Alpine Star — before getting off the mark at short odds in a maiden at Listowel in September.

Ridden by Ryan Moore at the Royal meeting, O’Brien’s charge was a ready winner but is down in trip and up in class this weekend.

“He seems to be in good form since Ascot. He obviously hasn’t done much,” said O’Brien, who sprang a 33-1 surprise last year with Sovereign

“He’s a horse we always thought would stay and that’s why he went to the race in Ascot. It will be interesting coming back to a mile and a half as well.

“I think he’s versatile enough ground-wise.”

Seamie Heffernan takes over from Moore, with Santiago one of six runners for Ballydoyle.

Among them is Arthur’s Kingdom, who is aided by first-time cheekpieces having finished second in the King Edward VII Stakes at Ascot.

“He’s in good form as well. Obviously he hasn’t done much since Ascot either,” said O’Brien.

“He’s a real honest, straightforward horse. Ascot was his first run of the year so it was a good run.” Iberia Dawn Patrol Tiger Moth and Order Of Australia complete the O’Brien team.

He went on: “Iberia ran well at Leopardstown and he’s in good form as well. Probably the better the ground the better it will suit him.

“He’s also a straightforward, honest horse. A mile and a quarter is as far as he’s gone yet.

“Tiger Moth won nicely over a mile and a quarter the last day on nice ground and seems to be in good form since then.

“We thought Dawn Patrol would stay further than the mile and a quarter and he seems to be in good order since the run, and Order Of Australia is another horse who looks like he might stay further than the mile and a quarter as well.”

Regarding the unusual circumstances of the race this year, coming before Epsom for the first time, O’Brien said: “It’s the first time all these horses have been over a mile and a half, it’s the fairest mile and a half in the world. Horses are going to come from out of the clouds in this race.

“Nobody is going to know what’s what until after this race. It’s so exciting, it’s incredible, really.

“After it we’ll know who is the best mile-and-a-half horse, what horses need to drop back to a mile and a quarter or even a mile. That’s the best thing about the Curragh, you know where you are going after it, we always think.

“We would usually like two runs well spaced out before the Derby, but most have only had one run. I think it will be the most exciting of all because there’s so much mystery in it.”

Joseph O’Brien takes on his father with the unbeaten Crossfirehurricane Galileo Chrome and the filly New York Girl

It is Crossfirehurricane, ridden by Shane Crosse, who appears his best chance.

“Throughout his whole career he’s been progressive, with each run he’s taken a big step up with a career-best last time out over 10 furlongs. He earned his spot by winning the Gallinule,” said O’Brien.

“He had a couple of runs on the all-weather, winning both impressively, and then he went on to the Gallinule last time.

“That was his first run over 10 furlongs and obviously the Derby is another step up by two furlongs, but if you’re not in you can’t win. He has a fantastic will to win.

“I’d be a little worried if it went very soft as he handles the all-weather well and won well on good to firm last time.”

Jessica Harrington will attempt to be the first female to train the Derby winner as she saddles Gold Maze

“He’s a horse with very low mileage. He’s actually still a maiden,” she said.

“He was third in the Beresford last year and on his first run this year he was just pipped on the post by Crossfirehurricane.

“I think he’s only learning his trade. I think he’s come on a lot from that run.

“The ground will have an ease in it. I was actually worried running him the last day on good to firm ground, but he handled it well. I think he’ll appreciate the ease in the ground and the two extra furlongs.”

This year’s race is notable for several trainers having their first runners in the race — Donnacha O’Brien with Sherpa Emmet Mullins with King Of Thrones, who will be ridden by Rachael Blackmore, Ger Lyons with Chiricahua and Andrew Slattery with Sunchart who was second to Santiago at Listowel.

The field is completed by Jim Bolger’s Fiscal Rules a running-on fifth in the Irish Guineas on just his second career start.