South Australian Derby favourite Odeon heads to his Group One assignment in Adelaide off a near-faultless campaign since being gelded.

Trained by Mathew Ellerton and Simon Zahra, Odeon has won three of his four starts this preparation and finished a close second in the other.

On that occasion in the Port Adelaide Guineas two starts ago, Odeon's jockey Jamie Mott was unsuccessful in a protest against Dom Tourneur on the winner Grand Chancellor.

Odeon stamped his Derby credentials with a strong win over 2000m against older horses at Caulfield on April 29 and Zahra has no concerns about the 2500m of Saturday's Derby at Morphettville.

"He was strong to the line the other day over 2000," Zahra said.

"His sectionals were good and his mother (Theatre Buff) won over 2400 metres twice.

"He's got a turn of foot and I think he thrives off good tempos. All his best races have been off strong tempos. To me the distance is not going to be a worry.

"We just need a bit of luck."

Damian Lane will ride Odean and could claim a Group One win in his fourth Australian state this season after success in Western Australia, Victoria and NSW.

Zahra said Odeon had been kept ticking over since his Caulfield win.

"He had a little gallop on Friday to keep him ticking over and he'll do a piece of work on Tuesday and that will be about it," he said.

"He's pretty fit now, nice and round and he looks good."

Odeon's spring campaign was cut short and he was sent to be gelded.

"He was just not concentrating and probably just wasn't quite there off his first preparation," Zahra said.

"We gelded him and he lightened off a bit so we gave him a spell and just targeted this Derby, instead of Sydney, with it being a bit later.

"It's all gone to plan so far and we've just got a week to go.

"He's been a different horse. He's always been a magnificent track worker and always shown us ability but he just got to the races and carried on."

Odeon is at $4 with another Victorian, the Ciaron Maher-trained Ruthven at $5.

Ruthven will be ridden by Mark Zahra.