Aidan O'Brien's charge swooped late to claim Group 2 honours under a fine Ryan Moore ride.

The Group 2 prize looked to be between Tower Of London and Vauban on paper, but jockey Gavin Ryan ensured he gave his mount Grosvenor Square every possible chance of landing the spoils and the pair found themselves with a mammoth advantage turning for home.

Grosvenor Square still had a thirty length-plus advantage as he entered the home straight and it looked very much as though he'd stolen the one-mile-six-furlong contest under an enterprising ride.

However, O'Brien's so-called second string began to paddle entering the final furlong. All the while, Tower Of London was starting to close the gap and Ryan Moore's mount soon devoured the ground to move upsides the longtime leader before swiftly passing him by for a very snug length and a quarter success.

Vauban, who briefly looked like throwing down a challenge in the straight, finished a further seventh lengths behind in third for Willie Mullins and Colin Keane.

"I'm delighted," said O'Brien on Racing TV. "Ryan gave him a class ride. He's a great horse and has a lot of class. He travels, he quickens, he stays. He loves fast ground and is a great horse to have."

"Ryan gave him a peach. I never thought he was going to get there. To tell you the truth, I thought Gavin Ryan was gone. At one stage in the straight, I think Gavin was a furlong in front!"

Tower Of London could be set to come back for the Irish Leger, while both the winner and the runner-up are potential candidates for the Melbourne Cup.

"He (Tower Of London) could come back here for the Leger.

"He's a great horse to have and can travel anywhere, he loves travelling. He could be a Melbourne Cup horse; he could be anything."

On the runner-up, O'Brien added: "Grosvenor Square ran a great race and he's a trip horse. He wanted to go the distance and could be a Melbourne Cup horse. He's a good economical galloper with a good staying pedigree."