Ryan Moore has completed the full set of British Classics by securing the St Leger on Capri at Doncaster with trainer Aidan O'Brien recording his fifth win in the race.

Firmly established as one of the best jockeys on the world, Moore was at his best as he drove Capri to victory over the persistent Crystal Ocean and Stradivarius.

Capri became the first horse since Nijinsky in 1970 to win both the Irish Derby and the St Leger.

The John Gosden-trained Stradivarius looked a real threat on the far rail, but Capri (3-1 fav) was already close to the pace and set sail for home inside the final quarter-mile (400m).

Crystal Ocean, trained by Sir Michael Stoute, then made a strong run from the rear, but Capri held the aces to score by half a length, with Stradivarius a short-head away third.

"When Crystal Ocean came to him, he dug in. He's done very little wrong in his career and has progressed from race to race," Moore said.

"He's shown he stays well, but he's an Irish Derby winner and that form looked very good. Everything had every chance, but he fought them off and was the best horse."

O'Brien said the Prix de l'Arc de Triomphe at Chantilly on October 1 had been discussed by owners Coolmore.

"He's a horse with a lot of class, which we saw in the Irish Derby," he said.

"Ryan had ridden him once before when winning the Beresford on him, but that was last season. I was a bit worried about that as well, but it all went great."

"We had it in our heads that if all went well today and everything went well after he could run in the Arc.

"Obviously the lads (Coolmore) will decide what they want to do - run him again or put him away."

Capri was cut to 20-1 from 25-1 for the Arc and 16-1 from 20-1 with RaceBets.