A winning double in feature two-year-old races at Caulfield has further clouded the Blue Diamond picture for Craig Williams.

Melbourne's premier jockey has ridden five leading Blue Diamond Stakes contenders to victory in the past five weeks and won't make a decision who he rides until after next week's Preludes at Caulfield.

Williams partnered Jukebox to win the Inglis Premier following up on Formality in the Chairman's Stakes on Saturday.

Next week he rides Catchy and Property in the divisions of the Blue Diamond Preludes while another possibility is Tulip who he rode on debut at Moonee Valley on December 31 before finishing second on the filly in the Blue Diamond Preview on January 26.

"It will be a tough decision," Williams said.

"Hopefully they all get there and I make the right decision."

Formality leapt to the top of Blue Diamond betting at $6 after her 1-1/2 length victory in the Chairman's Stakes.

Jukebox shares the second line with Pariah at $7 with Tulip at $8 and Catchy at $9.

Williams was taken with the wins of Jukebox and Formality, especially the latter.

"She was a little bit more nervous than the other group of horses, but wow," Williams said.

"She has speed and she did shut down mid-race and what I was impressed about when I got into the straight was how she quickened and then at the 100 metres she lowered and went again.

"She didn't get any more reminders just a bit more pressure.

"I was impressed with the win."

Lindsay Park co-trainer Tom Dabernig was equally taken with Formality's performance.

"She was able to show good speed from the gate but I like the way she got there and was able to relax," Dabernig said.

"When she was asked to dig deep she drew away again.

"She's got the pedigree and the performance and she's a really exciting filly."

Dabernig is expecting improvement to come from Formality ahead of the Blue Diamond Stakes on February 25.

"We try and use the lead-ups not as Grand Finals," he said.

"She's not fully wound up and there's improvement to come."

Dabernig says it will be a difficult decision for Williams to choose his Blue Diamond mount and Lindsay Park could have as many as six runners in the race.

"It will come down to barriers and conditions on the day," Dabernig said.

"I think Craig Williams will be very confused over what to do."