In what has already been an outstanding career, Joseph O’Brien broke yet more new ground on Saturday when his State Of Rest won the Cox Plate in Moonee Valley, Australia.

The AUS$5m contest is one of the biggest races in Australia and it truly was an Irish conquest as Cork native Johnny Allen, based in Australia, rode the colt to his dramatic short-head victory.

‘Both Allen and O’Brien had to wait anxiously when the rider of the runner-up Anamoe, Craig Williams, protested to the stewards after the race, prompting a 20-minute enquiry. State Of Rest came through with a strong run late on in the 10-furlong contest, edging slightly to his left and into Anamoe.

That was the latest incident in what has been something of a rollercoaster journey for State Of Rest and the members of O’Brien’s team that travelled to Australia. This is the first year that a new veterinary screening process for international runners has been introduced by the local racing authorities, following their own investigation into a spate of deaths in the Melbourne Cup. The new measures dissuaded the majority of European trainers from travelling to Australia and O’Brien was the only trainer outside of Australia and New Zealand to be represented in the Cox Plate.

O’Brien took particular issue with a mandatory scintigraphy scan which he said required State Of Rest to be sedated four times. He labelled the process a nightmare and admitted he had questioned his own decision to travel both State Of Rest and defending Melbourne Cup winner Twilight Payment to Australia.

Speaking at Leopardstown on Saturday, O’Brien reflected on the win, saying: “It was fantastic and I’m very proud of everyone, Mark Power and MJ Doran who are down in Australia with the horse and Mark Hackett in the office who organised the trip, transport and paperwork.

“I also have to thank the vets and everyone who organised all the veterinary side, which has been huge. It’s been a huge team effort and we were lucky to have keen owners with Richard Ryan, the manager (of Teme Valley Racing Club), and Jim Cockburn. Johnny Allen also gave him a fantastic ride.

“He’s a very tough horse with a great constitution and that’s why we were willing to give it a go.”

O’Brien continues to elevate his career to an outrageous standard. At just 28, he has now secured two Melbourne Cups, a Cox Plate and a Breeders’ Cup Mile among a plethora of Group/Grade 1 wins on the flat and over jumps.

Saturday for the O’Brien family got even better when Joseph’s father and brother were responsible for the first and second home, Luxembourg and Sissoko, in the Vertem Futurity Stakes at Doncaster.

Luxembourg, trained by father Aidan, remained unbeaten and became the Ballydoyle trainer’s 10th win in the race. He powered through to take up the running inside the final furlong and a half at Doncaster, and although failing to put a big distance between himself and the chasing pack, he always looked in control.

The son of Camelot is now as short as 6/1 for next season’s 2000 Guineas and is clear market leader at 4/1 for the Derby.