As a guide to the Derby, the Rosehill Guineas posed more questions than it answered.

Trainer Gerald Ryan hopes Saturday's Tulloch Stakes proves the right form race for the $2 million Classic on April 12 at Randwick.

Ryan was content to keep Koroibete at home on Saturday when the Guineas was run on a wet track and the reputations of a few leading contenders took a battering.

Criterion handled the conditions best for a decisive win but trainer Peter McKay was left scratching his head over Michael Walker's tactics on New Zealand Derby winner Puccini.

The colt was caught in a speed battle with Shamus Award and both weakened in the run home while Randwick Guineas winner Dissident, equal favourite on Saturday with Puccini, struggled in the wet ground.

"I'm hoping we will get a better track this week," Ryan said.

"He has probably been half a race behind so I think it is better for him to go over the 2000 metres and back up a week later over 2400.

"He has had three hard gallops recently and he's fit enough."

Koroibete is a $26 chance for the Derby with Criterion elevated to favouritism at $3.50 following his Guineas win.

The last horse to complete the Tulloch-Derby double was Starcraft in 2004, a year after Ryan won his first Derby with Clangalang.

Believe Yourself will represent the stable in the biggest race on Saturday's program, the $3.5 million Golden Slipper.

The filly earned the right to take her place in the field with victory in the Sweet Embrace Stakes.

She is a $26 chance with Earthquake the $2 favourite ahead of Tuesday's all-important barrier draw.

Believe Yourself is by the 2008 Slipper winner Sebring who has a Group Three sprint named in his honour at the meeting.

Ryan will have Dances On Stars and Hot Snitzel in the Sebring Stakes (1200m) while Temple Of Boom is also nominated to back up from his unplaced Galaxy run.