David Hayes' instructions to Craig Williams have proved spot-on ahead of Catchy's third-straight victory at Caulfield.

Lindsay Park co-trainer David Hayes told the jockey to allow Catchy to settle in Saturday's Blue Diamond Prelude and not worry about a perceived bias after horses racing on the speed won the the first two races.

Williams had Catchy second last of the eight runners settling down before landing the prize in the final few strides.

"David said don't worry about what people are perceiving the track to do. Just trust your horse and she'll let down for you," Williams said.

"Limestone made my filly work hard for it but I thought once we got on terms I was confident we were going to prevail in the end."

Sent out the $2.45 favourite to remain unbeaten, Catchy scored a short-head win over Limestone ($3) with Arctic Jewel ($6.50) 1-1/4 lengths away third.

Hayes said he was a little arrogant with his instructions to Williams, but it was all about getting the filly to relax.

Catchy was promoted to the top line of betting for the Blue Diamond Stakes on February 25 following her victory and Hayes is expecting a much tougher, high-pressure race.

"If you are an on-pacer, the faster they go, the harder it is to win," Hayes said.

"I know the Blue Diamond, run for a million-and-a-half dollars in two weeks, they'll run it pretty hard.

"Catchy showed she can come off the pace and that's she's a good, tough filly.

"There's still lots of improvement to come.

"We haven't squeezed her to win this so I know there'll be gas in the tank come Blue Diamond day."

Damian Lane, rider of the runner-up, said his filly had her chance to defeat Catchy and doubts Limestone can turn the tables in the Blue Diamond should connections decide to pay the $55,000 late entry fee.