Tommy Carmody's Royal Diamond 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.
Carmody said: "This is fabulous, much better than riding them!
"When you ride them you just come in, say your piece and then you're gone but when you're training them you live and sleep with them.
"We have a great team at home and Niall rides out regularly along with Ben Curtis, and Johnny Murtagh comes in to ride work when he can.
"We have 17 in training at the moment and it's all down to Johnny that I got involved.
"They're all very well-bred horses, bred to win St Legers and the like and Andrew (Tinkler, owner) is a fantastic man to train for."