Rostropovich and Idaho have given champion trainer Aidan O'Brien a big-race double at the Chester festival.

Courtesy of his impressive win in the Listed Dee Stakes, Rostropovich is now in the mix for the Derby while globe-trotting Idaho bounded clear to win the Group Three Ormonde Stakes in fine style.

The wet spring has held O'Brien's Classic team up but having had five races last year Rostropovich, the 5-2 favourite, did not lack for experience and knuckled down close home to win impressively.

"We were delighted with him. We thought maybe when he went beyond a mile it would suit him," said O'Brien.

"We didn't go beyond seven (furlongs) last year and we started him at a mile at Longchamp this year.

"We always hoped and thought when he stepped up it would suit him. He quickened up well. They went a nice, even pace. He relaxed lovely, so you'd have to be very happy.

"The lads will decide if he's one for Epsom or the French Derby. All the options are open to him."

Idaho (8-11 favourite) was third to Harzand in the Derby two years ago and has been busy since then.

A Royal Ascot winner in the Hardwicke Stakes last summer, his last four races had been in France, Canada, Japan and Dubai and down in class he made no mistake, winning by 3-1/2 lengths.

"The plan was to come here and then look at races like the Coronation Cup and King George, those sort of races," O'Brien said.

"Ryan (Moore) has said he'd stay further, though, so that opens up even more options. He said he'd have no problem going further, so I suppose he could develop into a Cup horse."