A 100th Group One win wasn't meant to be for Jim Cassidy at Randwick on Saturday but he could get another chance as soon as next weekend.

Cassidy was shooting to become just the third Australasian jockey to post a century of wins at the top level when he partnered Hawkspur in Saturday's Group One George Main Stakes.

But the Chris Waller-trained four-year-old never looked a winning chance, settling last before doing his best work late for fourth to Streama.

Cassidy was anything but disappointed and said his focus had not been on notching a milestone for himself, but in ensuring Hawkspur ran as well as he could.

"There's always another day," Cassidy said.

"I wasn't worried about that, I just wanted the horse to run well and he's done that so I'm very happy.

"He's on target."

There is no Group One racing in Sydney next Saturday but on Sunday, Melbourne hosts the Group One Sir Rupert Clarke Stakes meeting at Caulfield.

Cassidy confirmed he had been booked to ride last-start Danehill Stakes winner Charlie Boy who is to be nominated for both the Rupert Clarke (1400m) and Caulfield Guineas Prelude over the same trip for three-year-olds.