Australia's best racehorse is certain to return to England to show them what he's become after producing yet another supreme performance in the Group One Australian Cup.

Fiorente overcame an unfavourable run, a Cox Plate and a Melbourne Cup winner to add Flemington's autumn feature to its spring showpiece and to take his earnings beyond $6 million on Saturday.

The horse who left England as a promising but moderately performed young stayer will now attempt to add Sydney's richest race, the $4 million Queen Elizabeth Stakes to his tally.

Trainer Gai Waterhouse will then take her Melbourne Cup champion back to England to run at that country's greatest race meeting on the Queen's own racecourse.

"Why wouldn't I take him to Royal Ascot now," Waterhouse said.

"He's in supreme form and he's still only lightly raced - he's only had 18 starts."

In a contest that said a lot about Australian racing - and a lot about the new-found quality of its greatest race, the Melbourne Cup, imported gallopers filled the first five placings.

Fiorente, the $1.95 favourite, came from near last at the 500m, steaming home to score by a half length from another Melbourne Cup winner Green Moon ($18).

For Waterhouse, the win provided special satisfaction.

"I wanted to win this race and I knew I had the horse to do it," she said.

"The speed was on very early today there was pressure on the whole time. He was last, then he was caught wide on the turn and he just kept finding the line.

"No wonder the crowd loves him."

Fiorente has been a revelation since coming to Australia after a nine-race career in England where he was trained by Sir Michael Stoute.

Waterhouse secured him only weeks before the 2012 Melbourne Cup, reportedly paying $1.3 million for the Irish-bred galloper whose only wins had been in a maiden and a moderate Group Two race at Newmarket.

In one of his English runs he finished 13 lengths behind his stablemate Sea Moon who struggled home at the tail of the field in the Blamey Stakes at Flemington on Saturday.

Cox Plate winner and second favourite Shamus Award disappointed, finishing sixth after enjoying a relatively easy time in the lead.

"He was always going to be vulnerable against these seasoned, older stayers over 2000m here," said his trainer Danny O'Brien.