The owner who raced one of Gai Waterhouse's best horses is also hoping to play a role in the trainer's first Blue Diamond success.

Waterhouse has two runners in Saturday's $1 million Blue Diamond (1200m) at Caulfield as she looks to capture the only Group One for juveniles in Australia she hasn't won.

The Waterhouse-trained former champion colt Pierro won three of Australia's five juvenile Group Ones in 2012 for owners Greg and Donna Kolivos.

The Kolivos' also race Saturday's Blue Diamond contenders Nayeli and Francesco.

Nayeli is on the fourth line of betting at $9 having won her two starts including a dominant on-speed Chairman's Stakes performance at Caulfield three weeks ago.

Francesco is a maiden and was beaten almost three lengths by Diamond favourite Rubick last start but has shown talent on the track.

"I guess the difference between them is Nayeli has done it and she has won both starts by two lengths or more so you don't quite know how close to her ultimate ability we are," Greg Kolivos said.

"I guess we'll find out in a race like this.

"Francesco has still got to take that step but he was only two-and-a-bit lengths off a cracking two-year-old in Rubick the other day and was seven weeks between runs."

Kolivos said it would be a huge thrill if one of his horse's could give Waterhouse her first Blue Diamond.

Rival trainer Mick Price labelled Nayeli the forgotten horse this week with much of the attention centred on the other unbeaten runners Rubick and Earthquake.

Price has Jabali, runner-up in the colts and geldings Prelude, and Cornrow in the Diamond and says they are spot on but realises they face a daunting challenge in a quality line-up.

Jabali and Cornrow are expected to take up handy positions from barriers three and four respectively, with the trainer looking to experienced riders Damien Oliver (Jabali) and Luke Nolen (Cornrow) to produce the goods.

"My jocks will be in a position to make their own decisions. They are good gates. The horses are good beginners and they are at their top going into it," Price said.

"Certainly they won't be going back. They will be up there and they (jockeys) just have to make intelligent decisions on the day."

Rubick is the $2.90 favourite ahead of Earthquake at $3.60.