There is something special about both the Doncaster Mile and Australian Derby for Mark Newnham.

And on Saturday the trainer hopes he can get his name etched onto the honour roll of one, or both, of the time-honoured races at Randwick.

Newnham has forged a career in racing, starting as a strapper as a teenager and later becoming a jockey before working in a senior role for champion trainer Gai Waterhouse.

He began his training career in 2016 and now operates stables at both Warwick Farm and Randwick.

He has already trained the winners of four Group One races and hopes to add to it on Saturday with Shadow Hero one of the favourites for the Australian Derby while his stablemate Quackerjack is a lightweight hope in the Doncaster Mile.

The opening day of The Championships, featuring the Derby and Doncaster and two other Group One races, is one of the signature days on the Sydney racing calendar.

"I would say probably the signature day for someone like myself," Newnham said.

"I've spent my whole working life at Randwick.

"I've been fortunate to have four Group One winners already as a trainer and they've all been at Randwick.

"I've been watching Derbys and Doncasters since I can remember and to me they're two of the traditional Sydney races that are the pinnacle of our sport.

"We've got a couple of new races that are worth a lot of money but they don't have the history of a Doncaster or a Derby.

"So if we were to win either of them that would probably be my biggest day in racing."

Newnham says Shadow Hero is in great shape for the Derby while Quackerjack has been aimed at the Doncaster since earning a ballot exemption for his win in the Group Two Villiers over the Randwick 1600m in December.

Shadow Hero has won the Spring Champion Stakes (2000m) and Randwick Guineas (1600m) at Group One level and goes to Saturday's Classic off a last-start fourth behind Derby rival Castelvecchio in the Rosehill Guineas (2000m).

Newnham believes the way he found the line indicated he would handle 2400m.

"He's as good as he can be," Newnham said.

"He's had a really good preparation. He came through the Rosehill Guineas well. He was just disadvantaged by the way the track played.

"It was a race where his main rivals all drew inside him. He probably got further back than what would have been ideal and the way the track played made it very hard to make up ground, especially if you were out wide.

"His sectionals were very good. His last 600 metres was equal best of the race with Castelvecchio and his last 200 was the best of the race.

"And I'm happy to have him back at Randwick where he's had two starts for two Group One wins."