Aidan O’Brien holds a strong hand as he searches for back-to-back victories in the Breeders’ Cup Juvenile Turf at Santa Anita.

The one-mile contest brings the opening night of Breeders’ Cup action to a close, with the Ballydoyle handler winning the race for a record-extending fifth time with Victoria Road at Keeneland 12 months ago.

This time he has assembled a three-strong hand in quest for victory number six, as River Tiber, Unquestionable and Mountain Bear all face the starter in California.

Coolmore number one Ryan Moore has elected for River Tiber, who brings solid Group One credentials to the table having placed in both the Prix Morny and Middle Park since winning at Royal Ascot.

“We always thought River Tiber was a really good horse,” said O’Brien.

“His last two runs have been a little bit below par. In France he had a break before and we perhaps didn’t quite have him at his best and the last day we felt we didn’t have him at his best either.

“We think he has come right since Newmarket and I think he is rated 3lb below the other horse (Unquestionable) but he has always been a very classy horse and we think he is better now than he was for his last two runs. All the ducks weren’t in a row the last time.”

It will be the first time River Tiber has raced beyond six furlongs, but O’Brien is keen to test the colt’s credentials over a mile at a track which should play to his strengths.

Speaking during Breakfast at the Breeders’ Cup on Thursday, he added: “We always thought he would love stepping up to seven, so if we thought he would get seven at home, he should get a mile around here. He has a nice draw and a flat track and we’re looking forward to seeing what he does.”

Unquestionable has yet to get his head in front in Group company and was last seen finishing an honourable second to Rosallion in the Prix Jean-Luc Lagardere at ParisLongchamp.

Frankie Dettori comes in for the spare ride aboard the classy son of Wootton Bassett who has been knocking on the door all summer.

“Ryan was delighted with him in France and said the split just came a little bit too early for him and he had to go early,” continued O’Brien.

“Obviously when the split came he had to go and he would have just preferred to wait a little bit longer. He ran a very good race.

“We always felt a mile would be well within his compass and he’s in very good form and has a nice draw as well.”

The O’Brien trio are the sole European representation in a race the raiders have dominated since its inception, but there is a strong cast of American challengers lining up to take their chance.

Todd Pletcher struck in 2010 and will saddle the hat-trick-seeking Agate Road, while Michael McCarthy’s Endlessly is unbeaten in three and has track-and-trip form to his name.

Christophe Clement’s Carson’s Run accounted for My Boy Prince in the Grade One Summer Stakes at Woodbine, while the latter is joined by Can Group from Hall Of Fame handler Mark Casse’s well-respected stable.