He was sent out to make superior time to Fiorente, covering the 1400m in 1:33, returning 37.5 and 11 sectional times.
Carlton House ran his best race since joining Waterhouse's stable when he finished second to Opinion, after making the pace in the Parramatta Cup.
Given Carlton House never shirked the issue under 61kg, despite a frantic early tempo, it was a clear sign the entire is close to the form which had him rated a superior racehorse to Fiorente when they were stablemates in England.
With Cambridge-trained It's A Dundeel a formidable Ranvet rival, an in-form Carlton House gives Waterhouse some welcome extra firepower in a bid to win the Rosehill weight-for-age race for the eighth time.
"This is really serious racing now," Waterhouse said.
Fiorente will take his place in Saturday's field after an unbeaten two-start Melbourne autumn campaign where his prizemoney shot past A$6 million ($6.4 million) thanks to his Australian Cup win.
He returns to Tulloch Lodge with only one previous Sydney start to his credit when third in last year's All Aged Stakes - the race best remembered for the controversial defeat of former stablemate More Joyous.
A number of later-season options in Australia are under consideration for promising southern 3-year-old El Doute.
The son of Redoute's Choice will return to Michael Pitman's stable early next month and the Riccarton trainer will be spoiled for choice when confirming the colt's future.
"He's been treated for a quarter crack and that's why he didn't go north for the Derby," Pitman said.
"We had to back off him, but that might not turn out to be the worst thing and he's getting daily laser treatment and he'll be back in work in a fortnight to three weeks'.
"There's plenty of racing left in Australia for him and he could go to Sydney, Melbourne or Adelaide. There's a lot of options and there's 3-year-old racing in Sydney every week."
Pitman says El Doute can measure up in the best company and two runs back at Trentham he provided evidence of that. He finished fifth in the Levin Classic and less than 1 lengths off the winner Recite, despite racing three wide without cover.
He was then beaten a nose by the multiple stakes winner Include in the Dunedin Guineas after settling at the tail-end and finishing off strongly.
"His run at Trentham proved how good he is and he was right alongside Puccini [fourth] and company and at Otago he was ridden with the derby in mind and was only just beaten."
Part-owned by Black Caps captain Brendon McCullum, El Doute is a strapping son of the Swettenham Stud Stakes winner Ellicorsam and was bought on the Gold Coast by Pitman for A$90,000.
"I think he'll be top-drawer as a 4-year-old when he fills out a bit more," he said.
- additional reporting NZ Racing Desk
- AAP
