Rekindling led an Irish-trained one-two-three from Johannes Vermeer and Max Dynamite to win the A$6 million (Dh17m) Melbourne Cup at Flemington on Tuesday.
Rekindling, a three-year-old bay colt ridden by Corey Brown, gave young trainer Joseph O'Brien a win over his famous father Aidan in the 3,200-metre (two mile) handicap race.
Aidan O'Brien, who has set a world record this year with 27 Group 1 wins, trains Johannes Vermeer. Big Duke was the first Australian-trained horse across the line, finishing fourth.
"His preparation went really good. Corey gave him an unbelievable ride," Joseph O'Brien said.
"The lads at home and the lads here have done an unbelievable job. It hasn't sunk in yet."
Rekindling becomes the third Irish-trained stayer to win Australia's famous race following Vintage Crop (1993) and Media Puzzle (2003), and the sixth overseas winner overall.
Rekindling gave Australian owner Lloyd Williams his sixth Melbourne Cup success. He also owns runner-up Johannes Vermeer.
"It's terrifically exciting," Williams said. "We wanted someone who could ride the weight and a serious rider."
It was Brown's second win in Melbourne after jockeying Shocking in 2009.
"I can't believe it," the Australian jockey said. "It's so special, I've got my family here.
"It is a dream to even ride in the race. To come out and win it again, I'm lost for words. I'm honestly lost for words."
Rekindling also became the first three year old to win the Melbourne Cup since Skipton in 1941.
Johannes Vermeer, ridden by Ben Melham, looked the likely winner halfway down the long Flemington track before Rekindling's three kilograms weight advantage reeled him in.