Aidan O'Brien saddles up four runners in the Epsom Derby and his jockey son Joseph is in no doubt Australia is the one to beat.

A year ago, Joseph O'Brien chose to partner Battle Of Marengo only to see Ryan Moore partner stablemate Ruler Of The World to victory.

"I'm really looking forward to it. Since he came into the yard and since he started working he was always a very good horse," O'Brien told At The Races.

"He's bred to stay the trip, he's bred to handle the track and he's probably bred to win the Derby, which is what you need heading to Epsom.

"It's a great test of a racehorse.

"It's a day of racing like no other. It's the Derby and there is only one every year. It's the ultimate test of horse and rider.

"He has plenty of pace, hopefully he'll get the trip as that's a bit of an unknown, he's well balanced, his mum and dad handled the track well so we're looking forward to it."

By a Derby winner in Galileo, out of a multiple Group One winner Ouija Board, Australia is certainly bred for the job and he has dominated the market since finishing third in the 2000 Guineas.

The other runners from the O'Brien stable are Geoffrey Chaucer, unlucky when third in the Derrinstown Stud Derby Trial, Chester Vase winner Orchestra and Dee Stakes winner Kingfisher.

Moore is on Geoffrey Chaucer while Seamie Heffernan rides Orchestra and Colm O'Donoghue is on Kingfisher.