Tommy Carmody's Royal Diamond, runner-up in the Ebor at York, stepped up to Group One level to claim the Gain Horse Feeds Irish St Leger in a pulsating finish at the Curragh.
Jamie Spencer set out to give Aidan O'Brien's Fame And Glory a positive ride from the front and was still right in the firing line a quarter of a mile from home.
He looked to have everything at it in behind but Royal Diamond (16-1) and Niall McCullagh had moved powerfully for a long way and he stayed on again best after Massiyn and British raider Aiken collared Fame And Glory.
It was only right on the nod that Royal Diamond got the verdict from Massiyn, with Tom Dascombe's Brown Panther third after coming home as well as anything.
