Nash Rawiller's faith in Fiorente was justified at Moonee Valley on Saturday when the import flashed home to win the Group Two Dato Tan Chin Nam Stakes.

Sydney's premier jockey gave up the chance to win a $1 million race at Rosehill to continue his association with Fiorente, the horse he hopes can win him his first Cox Plate and Melbourne Cup.

Last year's Melbourne Cup runner-up brought up his first Australian victory, arriving just in time to deny outsider Spacecraft ($51) an all-the-way win in the 1600m weight-for-age race.

"I've probably given up the Golden Rose today and I think it's for good reason," Rawiller said.

The Gai Waterhouse-trained Fiorente ($3.20) got home by a long head with the Peter Moody-trained Lidari ($9.50) another short-head away third.

Favourite Super Cool was left flat-footed when they sprinted before the turn but picked up in the straight to finish fourth.

Rawiller labelled Fiorente "something pretty special" and despite the dominance of Atlantic Jewel in her two starts back from injury including her win in Saturday's Stock Stakes, the jockey won't be afraid to take her on in the Cox Plate.

"Not over a mile and a quarter," Rawiller said.

"She's the benchmark. He's proven today he can handle the Valley.

"Without getting carried away, the Cox Plate is going to be a different race to this again but I have got a lot of confidence in this horse."

Fiorente moved to $12 in the Cox Plate market with Atlantic Jewel a $2.70 favourite, while in the Melbourne Cup market Fiorente is on the second line behind Puissance De Lune.

In a pre-race controversy, last year's winner Happy Trails was denied a start by stewards after suspicions were raised that the horse may have been treated on race morning.

Stewards have opened an inquiry after Racing Victoria's compliance assurance team raided the horse's Caulfield stable on Saturday morning.

Super Cool's jockey Michael Rodd said the gelding raced like he was looking for further.

"I think now he's really looking like a Caulfield Cup-type horse. The 2400 metres is going to suit him," Rodd said.

Fiorente was the middle leg of a Moonee Valley treble for Waterhouse who also prepared Divine Calling and The Great Snowman to win.