Williams admitted to agonising for weeks over which two-year-old to ride in Victoria's most important juvenile event, maintaining that he was involved in an outstanding crop of two-year-olds.

But Catchy, a filly "who he fell in love with" the first time he sat on her back, made such an impression that he overlooked all the amazing offers of young talent to stay with her.

"I thought long and hard, I waited and waited but it was that feel I kept getting when I ride this filly, and I knew today when things looked grim she would win out on the day," Williams said.

Williams said he never worried that Sydney visitor Pariah looked to have opened up what looked to be a winning lead in the straight.

"No, I didn't – sure we were in a sticky spot but that belief I have in her kept going through my through my mind. She can do anything, she relaxes and she just keeps all her energy for race day," he said.

"Her efforts have been staggering, each day, each week, each month she gets better. Look, she even improved again from Caulfield last time. She's wonderful."

Catchy arrested the lead in the shadows of the post from Pariah. Both youngsters could well now add another dimension to this year's Golden Slipper stakes in three weeks' time.

Peter Snowden said of Pariah: "I was very proud of him, he's going to be a very good colt in the spring, I don't know about the Golden Slipper – he's had two trips away from home now and that's not easy," Snowden said.

David Hayes and his training partners did what they threatened to do on paper and that was to dominate the Diamond, having three of the first four over line.

Catchy has maintained an unbeaten start to her career, storming home to win the Blue Diamond Stakes at Caulfield at her fourth start.

Williams was spoiled for choice, having ridden five of the leading contenders heading into Saturday's race, but stuck with Catchy. Catchy's stablemate Formality was third.

Catchy has added to Hayes' record haul for a trainer in the Blue Diamond, his sixth win in Victoria's premier juvenile race and his first since forming a partnership with his son Ben and nephew Tom Dabernig.

"I am a very lucky man to have won this race so many times [now six]. My father won two and it's been very good to my family," Hayes said.

"We will now give plenty of thought to the Golden Slipper she is very very good, Catchy. In the same group as Miss Finland, I think."

Stablemate Tulip was fourth.