The absence of a crowd will not dull Josh Parr's excitement if he can capture the ATC Australian Derby on his personal pin-up horse Shadow Hero.

Parr feels a sense of unfinished business with the three-year-old, who was the beaten favourite in the Victoria Derby last spring.

He has warned punters not to judge Shadow Hero's stamina on his Melbourne performance and says his gut feeling is the three-year-old will relish the 2400 metres at Randwick.

"The Victorian Derby is an unfair assessment of him in regards to the distance and conditions of the track," Parr said.

"At that point in time he was at the end of his preparation and the trip down may well have just tipped him over the edge.

"This preparation he is a stronger horse physically and mentally and his physical condition says to me he is still coping OK with the preparation.

"From the first time I rode him, he gave me the feel he could win a mile-and-a-half Derby. And I still think that."

Shadow Hero has jostled with Cox Plate runner-up Castelvecchio for honours as Sydney's best middle-distance three-year-old.

He got the verdict over the Richard Litt-trained colt in the Spring Champion Stakes and again in the Randwick Guineas before Castelvecchio turned the tables in the Rosehill Guineas.

The pair clash again on Saturday and adding to the intrigue is the presence of Victoria's Classic winner Warning and New Zealand Derby winner Sherwood Forest.

Parr expects it to be a race for the ages.

"He's one of the headline horses, Shadow Hero, and I'm excited for the race," Parr said.

"It is one of our most prestigious races. It's usually an exciting race and I think this year's field has the potential to produce a really exciting contest."

Parr has already had cause for celebration away from the track.

His wife Amanda gave birth to their second child, Sadie, last week and both mother and daughter are back home and well.

While his house now has all the added noise and energy that comes with a newborn, the jockeys' room is a different story.

Strict biosecurity measures have meant riders are split into small groups and segregated into various rooms, only seeing each other when they are legged up in the mounting enclosure.

"The usual environment in the jockeys' room is loud, people are commenting on this and that," Parr said.

"There is a lot of atmosphere in the jockeys' room but at the moment we're all split up. It's really different."

So too is the atmosphere outside with only essential officials and participants allowed on course.

But for Parr, who has been inseparable from Shadow Hero since the start of the spring, the sound of finishing first in the Derby will be noise enough.