Order Of St George completed a St Leger double for Aidan O'Brien with a runaway victory under jockey Joseph O'Brien.
However, the race produced more sadness than jubilation after last year's winner Brown Panther sustained a fatal hind leg injury nearing the turn for home.
The decision to reroute Order Of St George to the Irish St Leger instead of the Ladbrokes St Leger on Saturday proved an inspired move by connections as he eased to success while Bondi Beach scored at Doncaster in his absence.
O'Brien anchored the well-backed 5-4 favourite at the back of the pack as Good Tradition set a solid pace in front with Brown Panther taking up a role behind the leader and clear of the main pack.
The race changed dramatically approaching the turn for home as Richard Kingscote sent Brown Panther in pursuit of the leader at which point disaster struck and the popular seven-year-old was pulled up. He could not be saved.
Owen: "I can't bear thinking of life without him"
Former England international Michael Owen has been a longtime lover of horseracing but there is little doubt Brown Panther was the horse he loved the most.
Bred by Owen out of his first racehorse Treble Heights, Brown Panther reduced his owner to tears when winning at Royal Ascot in 2011 and provided him with a first Classic win in last year's Irish St Leger as well as a host of other big-race wins.
Speaking in June, Owen told the Racing Post's Lee Mottershead of his affection for Brown Panther, saying: "I can't bear thinking of life without him. It's that bad.
"I'll always love racing but I can't imagine I'll ever be able to replicate the pleasure he has given me over the last half a dozen years. I don't think anyone could get as much pleasure from a horse as we've had from him."
With front-runner Good Tradition weakening, Order Of St George powered through the pack and shot clear, his superiority over the rest of the runners there for all to see as he pounded clear.
Order Of St George crossed the line 11 lengths in front of Agent Murphy, who ran on resolutely in the closing stages to take second from Wicklow Brave in third.
Joseph O'Brien, who was winning the race for the first time, said: "He's a lovely horse who handled the ground and stays well. He's very genuine too and was really good today.
"I was a bit further back than I intended and I had a quick look at the top of the hill and made my move a bit earlier than I should have as I didn't want the leader [Good Tradition] to get away, but I ended up there sooner than I wanted. Fortunately he has a big engine and fought all the way to the line."