Magician will spearhead Aidan O'Brien's bid for a seventh St James's Palace Stakes success at Royal Ascot today after overcoming a late scare.

Bruising that the Irish 2000 Guineas winner suffered in a knock on Thursday has disappeared and he is poised to take his chance in what has the makings of a vintage renewal of the Group 1 over a mile.

Magician's pilot Joseph O'Brien, son of the Ballydoyle handler, is looking forward to the contest and the chance to take on Newmarket 2000 Guineas victor Dawn Approach, who ruined his chance in the Investec Derby when refusing to settle for much of the mile-and-a-half journey.

"He'll be checked over before he gets on the box, but at the moment I think he's good and ready to go," said the jockey.

"It's a good race. Dawn Approach is a high-class horse and I'm sure if they didn't think he was 100%, he would not be running. You can't fault him if you take the Derby run away, but we're hoping our horse can put it up to him."

Victory would stake Magician's claim to be champion three-year-old in Europe over a mile. O'Brien Sr said: "He looks an incredibly exciting horse. The lads [Coolmore] made that decision [to run in the Irish Guineas] – I wouldn't have been brave enough to bring him back in trip [after the Dee Stakes over a mile and a quarter]. It was a great decision on their part and it clearly paid off.

"He's a horse with a lot of class – he travels very strongly and keeps on going. He has a lot of speed. Everybody saw at the Curragh how strong he travelled. I'd hope he'd never have to go much further than a mile and a quarter. Whether he has to go further than a mile, I wouldn't be sure."

Ryan Moore gets the leg up on Mars, the O'Brien second string who drops back in trip after finishing sixth behind stablemate Ruler Of The World at Epsom.

"He's a high-class horse with loads of ability and, hopefully, he can put it all together," said O'Brien Sr. "He won his maiden and he's only run in Group 1s since, so he's been thrown straight in at the deep end. He ran well in the Guineas and the Derby and, hopefully, he'll run a nice race again."

O'Brien Jr feels it would be foolish to overlook Mars' prospects. "We think he could be a little like Rip Van Winkle in that he had the stamina to run well in a Derby but has the speed to run well over a mile," he said. "In his work he hits 40mph which is very fast, so he might be better off coming back down in distance."

Outsider George Vancouver completes the O'Brien trio in a nine-runner line-up.

Toronado was a big disappointment when only fourth in the 2000 Guineas, but connections have worked tirelessly to ensure the colt has every chance of being seen at his best at Royal Ascot.

"We know we did not see the real Toronado in the Guineas, but everything he has done at home since he resumed exercise has convinced us that we still have the real deal," said trainer Richard Hannon.

"We believe that he suffered a displaced palate as soon as he left the stalls at Newmarket, so he did remarkably well to finish fourth."

The 2000 Guineas form has been knocked because 150-1 shot Glory Awaits took second place, five lengths behind Dawn Approach.

However, his trainer Kevin Ryan dismisses the doubters in the belief that the application of blinkers has made all the difference.

"We were very hopeful we could trouble the top two in the betting [at Newmarket]," he said. "We always felt the blinkers would bring out an improvement. His work has been very good since the Guineas – the blinkers have really put him on his A-game."