Cao Cao stamped himself as a Blue Diamond prospect during the spring and jockey Mark Zahra is eagerly awaiting the colt's return after partnering him to his latest jump-out win at Caulfield.

Zahra rode the Mick Price-trained colt in his two spring starts for a second in the Maribyrnong Plate and a convincing win at Moonee Valley in late November.

He has been aboard Cao Cao in two recent jump-outs including Tuesday morning and believes he is on target for his scheduled return in the colts and geldings Blue Diamond Prelude on Saturday week.

"He was very sharp. I sort of expected him to win that trial against some young unraced horses having their first trial, but he was really good. I couldn't be happier," Zahra said.

"He flew out of the gates and it was as quick as he's been out actually.

"He smoked along and I just gave him a little squeeze up the hill and he trialled really well.

"I'm looking forward to him going to the races. I think he's improved for sure."

The Blue Diamond Preludes are two weeks before the Group One Blue Diamond (1200m) at the same track.

Cao Cao was among 79 juveniles paid up on Tuesday at the third acceptance stage for the $1.5 million Blue Diamond, and is one of eight from the Price stable still in contention.

Price trained the quinella last year with Extreme Choice and Flying Artie.

Lindsay Park trainers David and Ben Hayes and Tom Dabernig have the most horses still in the entries with 13, including Catchy, Tulip and Formality.

Snowden Racing has two entries including Canonbury Stakes winner Pariah.

The Snowden Racing partnership of Peter Snowden and his son Paul won the Blue Diamond two years ago with Pride Of Dubai.

Peter Snowden also won with Earthquake (2014) and Sepoy (2011) when he was head trainer for Darley.

Blue Diamond Preview winners Limestone and Property are still not nominated but connections have until February 20 to decide whether to pay a $55,000 late entry for the race on February 25.

Final acceptances are taken on February 21.