Never one to shy away from a Group One challenge, trainer Anthony Cummings admits he had to be persuaded to run Fiveandahalfstar in Saturday's Victoria Derby.

Cummings avoided the traditional lead-up races in Melbourne, preferring to let the gelding establish winning form with two victories in restricted races in Sydney.

After his all-the-way win at Rosehill on Saturday, the trainer picked out an 1800 metre race at Flemington on Thursday but was persuaded otherwise by race jockey Damien Oliver.

"Damien came and rode him on Tuesday morning at Caulfield and thought the Derby was where we should go," Cummings said.

"There are lots of boxes he had ticked to make the Derby possible.

"It's a tight time frame and he has had a lot of racing but he turned up in Melbourne in great shape.

"He's big and strong. He enjoys his work and looks as if he will savour the 2500 metres."

Cummings said the form of Derby favourite It's A Dundeel had been a deterrent until he suffered his first defeat in the Vase at Moonee Valley.

"We paid up for the Derby all the way through but the way It's A Dundeel dominated in Sydney put me off," he said.

"I never like to go in with an expectation of running second and while the race wasn't run to suit the other guy last week it proved he's not infallible."

Fiveandahalfstar goes into the Derby at his seventh start for the preparation, his most recent two producing his first two wins.

The seven-day back-up is not a concern with two of his races this campaign within three days.

Fiveandahalfstar is a son of Hotel Grand who Cummings trained to Group One wins in the 2005 Spring Champion Stakes and 2006 Randwick Guineas.

New Zealander It's A Dundeel remains favourite for the blue riband with TAB at $2.80 ahead of Honorius, Super Cool and Hvasstan all at $7.

Fiveandahalfstar is a $26 chance.

It's A Dundeel was beaten by Super Cool in the Vase (2040m) but trainer Murray Baker was unconcerned.

Baker thought long and hard about running the colt at the Valley but decided he would benefit from racing in the left handed direction having gone the other way at his previous starts in New Zealand and Sydney.

"I'm pleased we did it," Baker said.

"We hadn't done a lot with him for three weeks after the Spring Champion Stakes and he probably needed it."

The Baker-trained Lion Tamer won the 2010 Victoria Derby by many lengths, leading all the way on a wet track.

Baker said It's A Dundeel was a completely different type of horse.

"Lion Tamer was versatile and could win from anywhere," he said.

"This guy is a genuine staying horse who gets back in his races and we won't be changing that."