Order Of St George provided Aidan O'Brien with his second St Leger victory in as many days when romping away with the Irish version.
O'Brien's Bondi Beach was awarded the St Leger at Doncaster on Saturday after being caused interference by Simple Verse and Order Of St George followed up at the Curragh.
However, the race was marred by a fatal injury suffered by last year's winner Brown Panther midway through the contest on his return from a previous injury.
Good Tradition set a stiff pace from Brown Panther in the early stages, but Richard Kingscote quickly pulled up the Tom Dascombe-trained horse around the halfway point.
Dermot Weld's Good Tradition folded with more than half a mile still to run as stablemate Forgotten Rules took over from Second Step and Gospel Choir.
Joseph O'Brien, though, was making smooth progress from the rear aboard Order Of St George, who had been pulled out of the Doncaster St Leger in order to wait for the Irish equivalent.
The only three-year-old in the contest then eased into the lead from Second Step and kept on galloping to the line by an ever-widening margin to the rest of the field.
Order Of St George showed no signs of stopping as he beat Agent Murphy by 11 lengths, with Wicklow Brave staying on for third as Second Step paid for his effort early in the straight by dropping back to fourth.
