Kevin Moses never won an ATC Australian Derby during his time as a premiership-winning rider but Tim Clark can understand the groundswell of support about his chances of training this year's winner.

On breeding there isn't a lot that is fashionable about the Moses-trained Singing Flame yet Clark insists the horse's bloodlines are the key to his chances of landing the $2 million race at Randwick on Saturday.

Singing Flame is by Song Of Tara, a stallion who stood in southern NSW without the fanfare of his Hunter Valley contemporaries but one who has earned the respect of trainers and jockeys who have dealt with his progeny.

"They are honest, genuine, no-frills horses," Clark said as he prepares for what he rates as his best Derby ride.

Song Of Tara's progeny are also known as superior wet-track horses and Clark is banking on that asset to challenge a lead-up trend into the race.

"Any more rain will bring him into it and it makes up for what he might lack in class," Clark said.

Singing Flame has firmed in Derby betting with every start this campaign and earned more admirers with a Tulloch Stakes placing last week that almost defied belief.

He is into $11 with most bookmakers with the Rosehill Guineas winner Criterion holding his place as the $3.50 favourite from the New Zealand Derby winner Puccini ($6).

Singing Flame raced wide for the first 1000m of the Tulloch Stakes, found comfort with some momentary cover before being asked to sprint again to keep his rhythm going.

It was left to Gallatin, who threaded his way through the field from last with an uninterrupted run, to snatch the race in the last 50m.

"I went from looking like a genius at the furlong (200 metres) to being a mug but if I had it over again I wouldn't have done too much different," Clark said.

"He had his momentum up so I wanted to keep rolling."

The Rosehill Guineas has been the definitive guide to the Derby with seven of the last 10 winners coming out of the 2000m lead-in.

Form out of the Tulloch Stakes last held up through the 2004 Derby winner Starcraft but Clark says it can be revived this year.

"History and statistics will probably say the Rosehill Guineas is the best race going into Saturday but it looks an open Derby to me," he said.