Aidan O’Brien’s regally-bred colt has been a warm order for the blue riband Classic ever since beating the highly-regarded Free Eagle last September.
He was beaten on his return to action this season in the Qipco 2000 Guineas, but his pedigree suggests he can only improve for stepping up in trip.
The fact that two of the three horses to have run from the 2000 Guineas have subsequently won the Irish Guineas and the Dante and French Derby, in Kingman and The Grey Gatsby, also gives him solid claims.
As well as a big field and wide draw, though, Australia may also have to overcome softer ground than ideal with heavy showers forecast for Saturday morning.
Clerk of the course Andrew Cooper said: “We’ve had a lovely drying day today and the going is predominantly good with the odd softer patch, I’d say we’re heading towards good for the Oaks.
“Potentially there is rain forecast for Saturday, but how much confidence you place is those forecasts I don’t know.”
A victory for Australia would be bad news for William Hill who have him as their 11-8 market leader and also report strong support for his two stablemates, Geoffrey Chaucer and Orchestra.
Last year Joseph O’Brien chose to ride Battle Of Marengo only to see Ryan Moore partner stablemate Ruler Of The World to victory, but there was never any doubt he would be on Australia this time.
Moore is on Geoffrey Chaucer, while Seamie Heffernan rides Orchestra and Colm O’Donoghue is on Kingfisher.
Snow Sky will not run after failing to adequately recover from a minor setback.
The Michael Stoute-trained colt entered the Classic picture when winning the Lingfield Derby Trial, but it emerged on Wednesday morning that he had banged a joint.
Stoute and Teddy Grimthorpe, racing manger for owner Khalid Abdullah, had been hopeful of Snow Sky recovering in time to run but confirmed he will miss the race and head to Royal Ascot instead.
There is a strong Irish challenge outside of the Ballydoyle quartet, with the first two home in the Derrinstown taking their chances.
John Oxx’s Ebanoran was first past the post that day but Dermot Weld’s Fascinating Rock was awarded the race by the stewards after the pair got very close in the finish.
Oxx has only had three runners in the Derby, but has won it twice.
He said: “I can’t really make any comparisons with my two Derby winners (Sinndar and Sea The Stars) as it is too early – Ebanoran has not won a significant race yet. He is quite an idle worker at home, like Sinndar, so doesn’t give us too many clues about the extent of his ability.”
Meanwhile O’Brien’s Marvellous heads into this afternoon’s Oaks with plenty of stable confidence behind her.
Relatively unconsidered until shooting clear to win the Irish 1,000 Guineas at the Curragh in heavy ground, that performance suggested she would have no trouble with an extra half a mile, although despite being by Galileo, she is out of a Cherry Hinton winner.
“There’s a lot of speed in Marvellous’ pedigree, but she’s by Galileo and they stay well,” said O’Brien.
Joseph O’Brien overlooked Marvellous at the Curragh but is back on board at Epsom.
He said: “She won well in the Irish 1,000 Guineas, you’d imagine she’d get a mile and a half.
“It was very heavy ground and she looked to go to the line well. Hopefully she’ll handle the better ground and get the mile and a half, she’s in with a fighting chance.”
Ralph Beckett saddled a famous one-two 12 months ago when Talent led home stablemate Secret Gesture, and is double-handed again after supplementing Lingfield Trial winner Honor Bound.
“Honor Bound has surprised us all. I was only hoping for black type at Lingfield,” said Beckett.
“She doesn’t work well at home and you wouldn’t spot her in a crowd. But she’s got the pedigree for it. She’s a half-sister to Treasure Beach, who never won by too far, and he crept through the ranks like her.
“Whether she’s capable of winning an Oaks is another question, but she deserves her chance.
“I was pleased with Regardez when she was third in the Musidora, where she came off a slow pace, looked like she was going to drop back and then ran on. I was doubtful whether she’d stay before that. Richard (Kingscote) won on her last year and his style of riding will suit her.”
David Simcock also has two runners in Madame Chiang, winner of the Musidora Stakes at York, and Momentus, who was third at Lingfield.
Simcock took Madame Chiang to Epsom for the Breakfast with the Stars morning and was happy with how she handled the track under William Buick.
“William said that coming down the hill she switched on to the right leg straight away and it is very pleasing. It was only a routine canter but all worked out very well,” said Simcock.