Chris Waller finds it impossible to fault Catkins for her return in the Breeders Classic but it's still not enough for the trainer to say she will win the race for a second time.

"I never expect them to win because it just sets you up for a fall," Waller said.

"But we picked this race out a long time ago and if she's come back as good as she was last year she will be very hard to beat."

On that score Waller insists the popular grey mare will have no excuses at Rosehill on Saturday as she tries to improve her first-up record to six wins from seven attempts.

"She's had a perfect preparation, two trials, her work's been good leading into it," Waller said.

In contrast to a 2014 autumn campaign that also netted wins in the Wiggle Stakes and Emancipation Stakes as well as a Group One placing in the Coolmore Classic, Catkins managed to post just a lone spring victory.

"I didn't know what to make of her spring form. It was hard to fault her but she was clearly a length below her best form," Waller said.

Bookmakers seem more certain of Catkins' prospects than her trainer because she has been odds-on throughout most of the early betting on the Breeders Classic, a Group Two event.

She is well treated under the handicapping conditions of the race with 57kg and her prowess from the barriers almost ensures there are few concerns about a deep draw.

"This race will tell us if she has come up as well as last year," Waller said.

"We'll set her for the Queen of the Turf (Stakes). Stretching her out to the mile will be tough but if you are picking up Group Two races along the way you shouldn't be too disappointed."

Waller has Arinosa resuming against Catkins but the favourite's main opposition is tipped to come from the last-start Randwick winner Mihiri.