A spat between high-profile owner John Singleton and trainer Gai Waterhouse has overshadowed a star performance by All Too Hard to win the All Aged Stakes at Randwick.

The race had been billed as a showdown between Singleton's star mare More Joyous and All Too Hard, who was having his final race in Australia.

In the end only All Too Hard figured in the finish, calling on all of his class to overhaul early leader Rain Affair in the shadows of the post.

More Joyous loomed to win the race topping the rise but weakened in the concluding stages to finish seventh.

Singleton was clearly upset by the performance and said he did not want More Joyous to run today because of an injury.

He told Channel Seven that Waterhouse had passed information of the injury onto her bookmaker son Tom, and that he would pull his horses from the Waterhouse stable as a result.

"I was going to have $100,000 on her," he said.

"When her own son is a bookmaker saying [More Joyous has] got problems I didn't know about, well you have to ask the racing officials, you have to ask Gai, you have to ask Tommy.

"All I'm saying that as an owner there's too much conflict of interest. All my horses are leaving Gai tomorrow."

Tom Waterhouse denied knowing of an injury to the horse.

"I never said that it had problems, I never knew that it had problems," he told Channel Seven.

"Mum wouldn't have started it if it had problems."

The Waterhouse stable declined to comment on the allegations.

There has been bad blood between Singleton and Waterhouse since the hall of fame trainer chose an outside barrier for More Joyous in last year's Cox Plate.

The mare subsequently was trapped wide throughout the run and finished 11th.

'Up with the best'

All Too Hard and Dwayne Dunn have proved to be an unbeatable combination this autumn. ( AAP: Dean Lewins )

The post-race controversy took the gloss off what was a dynamic performance by All Too Hard, who was resuming after developing a temperature before the Australian Guineas early last month.

"It's been a long road but you just can't describe him - he's got the bloodlines, the pedigree and just kicks some arse," said Michael Hawkes, who trains the colt alongside father John and brother Wayne.

"He hasn't raced for 60-odd days and to do what he's done today and pull out all stops takes a gutsy horse.

"He's up there with the best we've had like Lonhro, and Wayne and I've been lucky enough to be along with dad for the ride."

Result 1 - All Too Hard 56.5kg $2.80 fav T: Michael, Wayne and John Hawkes J: Dwayne Dunn 2 - Rain Affair 59kg $11 T: Joe Pride J: Craig Williams 3 - Fiorente 59kg $51 T: Gai Waterhouse J: Tommy Berry Margins: 1/2L x 1-1/4L Time: 1:22.89 Last 600m: 36.18

Just like his former great rival Pierro, All Too Hard will begin stallion duties this spring.

While the half-brother to Black Caviar was snapped up by Vinery Stud late last year, Pierro was only yesterday bought by breeding giant Coolmore in a reported $30 million deal.

The connections of All Too Hard must now decide whether to press on with a trip to England and contest the Queen Anne Stakes (1,600m) at Royal Ascot.

The owners are keen to go but Team Hawkes will let the dust settle before making a decision.

"He'll strip fitter for today and we'll talk with the shareholders and we'll probably know in the next couple of days," Michael Hawkes said.

"The horse comes first."

Regardless, the colt bows out of Australian racing a winner of four Group Ones - the only horse to win the Caulfield Guineas, CF Orr Stakes, Futurity Stakes and All Aged Stakes in the same season.

Rain Affair was brave after leading the field until the final strides, while Melbourne Cup runner-up Fiorente produced a slashing run fresh to finish third.

Group One-winning colt Epaulette ranged alongside of All Too Hard in the straight but gave ground late to finish sixth.

Jockey Nash Rawiller said More Joyous travelled well but changed stride in the straight.

"She didn't quicken like she normally would," he said.

"I just wasn't happy with her, she just wasn't herself."

Champagne performance

Earlier, talented filly Guelph produced a remarkable performance to grab a last-gasp victory in the Group One Champagne Stakes.

Jim Cassidy almost pinched the race with a daring front-running ride aboard Fuerza ($26), but Guelph ($2.50 fav) made up more than six lengths in the straight to steal victory in the final stride.

Result 1 - Guelph 54.5kg $2.50 fav T: Peter Snowden J: Kerrin McEvoy 2 - Fuerza 56.5kg $26 T: Bjorn Baker J: Jim Cassidy 3 - Equator 56.5kg $20 T: Gai Waterhouse J: Nash Rawiller Margins: nose x sht nk Time: 1:36.28 Last 600m: 37.00

The winning margin was a nose, with a short neck back to Equator ($20) in third.

It was a memorable finish to the 150th running of the Champagne, the final leg of Sydney's two-year-old triple crown.

Guelph claimed the second leg, the Sires Produce, on the back of a strong fourth behind Overreach in the Golden Slipper.

Few can disagree with Snowden's assessment that Guelph is among the country's top juveniles this season.

"I was thinking she got a mile too far back and I thought she had too much to do," a relieved Snowden said after Champagne.

"I think what she's done shows what she's made of in that she had a Blue Diamond campaign and then the Slipper.

"To back up and win the Sires and the Champagne is a testament to her ability and her toughness."