The best Melbourne two-year-olds are still building towards Group One racing, presenting a black-type opportunity for Certain Ellie in the Chairman's Stakes at Sandown.

Paul Rocke is under no illusion the filly is a rung or two below the top echelon of youngsters, ensuring the trainer will be more than happy with a top-three finish in Saturday's Group Three race.

The filly is not among nominations for the Blue Diamond Stakes on February 28 and she may even be in Adelaide on that day chasing a win in the Listed Cinderella Stakes over 1000m at Morphettville.

Rocke tested the waters in Adelaide last month when the filly led throughout over 1000m at Morphettville Parks.

He said taking the filly to Adelaide meant she dodged Fontiton in the Blue Diamond Preview while it gave her valuable experience on how to cope with a long float trip.

"We thought we would go over there where we could win and get the prize money," Rocke said.

"She's now got a city win under her and being a Not A Single Doubt filly it helps her as a future broodmare.

"A lot of these horses on Saturday are trying to win and get into the Blue Diamond, but for us it's more like her grand final.

"I think she'll get 1200 (metres) but for this prep we'll keep her to the shorter trips and if we can get her a placing in a Group Three it would be fantastic."

Rocke said Certain Ellie used her pace when successful in Adelaide but he knows it will be a different scenario in the Chairman's.

Certain Ellie relegated the short-priced favourite Stoker, who lines-up in the Inglis Premier on the Sandown card, into third place after that gelding had chased home the highly regarded Headwater on debut at Moonee Valley.

Certain Ellie is one of the Chairman's outsiders $41 with the Danny O'Brien-prepared Prompt Return the $3.30 favourite ahead of the David Hayes' Haybah at $4.20.