Aidan O'Brien became the first trainer to win three successive Epsom Derby's on Saturday as favourite Australia prevailed in a thrilling race.
Australia, ridden by O'Brien's 21-year-old son Joseph, repelled a late challenge by Kingston Hill (15/2) to take the honours at 11/8 while Romsdal was third at 20/1.
Australia, O'Brien's fifth winner in the race considered the 'blue riband of the turf', follows Camelot and Ruler of the World in giving the Irish trainer his hat-trick.
Third in the Qipco 2000 Guineas off the back of O'Brien's claims the regally-bred colt is the best horse he has ever trained, the son of Galileo travelled beautifully throughout.
Having hit the front over a furlong out the 11-8 favourite kicked clear of Kingston Hill and while it looked like he may go away and win by further, he still had a length and a quarter to spare from Roger Varian's gallant runner-up.
John Gosden's Romsdal outran his 20-1 price to finish third, another three and a quarter lengths away.
The placed horses from the Dante, Arod and Godolphin's True Story, were just behind the main protagonists with Red Galileo running a massive race, too.
By a Derby winner in Galileo out of an Oaks winner in Ouija Board, the blue riband Classic was the race Australia was destined to win.
Joseph O'Brien looked confident throughout on the chestnut, sitting on the outside of the 16-runner field in mid-division.
He moved into contention so stylishly, having come down the famous hill without a hitch. Andrea Atzeni gave Kingston Hill every chance and took over at the head of affairs with a quarter of a mile to run, but in truth he always looked a sitting duck for the market leader.
Winning rider O'Brien said: "I had a grand position and was going very easily coming down hill, nearly too easy. "I got there a bit too soon, I was cantering all the way – I got there too soon but I had to stay going when I did.
"Horses don't come easier to ride than this fellow – he's the best (I've ridden)."
Aidan O'Brien said: "We're in a very privileged position to have the horses we have, so it's thanks to everybody. There are so many people involved just to get him to this position.
"Joseph had it in his mind where he wanted to be all the time, to keep it uncomplicated and safe and that is what he did – he gave him a beautiful ride.
"We said what we thought (about him being best Flat horse O'Brien has trained). Maybe it is best to say nothing, but we've always thought he was very special – the way he is bred makes him very special.
