Rival jockey Nash Rawiller is adamant the trainer tipped to give Jimmy Cassidy his 100th Group One winner is also the one who can deny him the milestone at Randwick on Saturday.

Cassidy rides the Chris Waller-trained Hawkspur in the George Main Stakes in his bid for a century of Group One wins.

But Rawiller likes the chances of his mount and stablemate Royal Descent spoiling the moment despite early betting pointing to a Hawkspur win in the weight-for-age race.

"Nothing has really gone her way in her first couple of runs back and tomorrow she gets her chance to show what she's made of," Rawiller said.

"She has drawn the right barrier to get a lovely run and I expect her class to take her a long way.

"She will be very hard to beat."

Hawkspur ($2.70) is clear-cut at the top of George Main betting after he disposed of his Chelmsford Stakes rivals with a brilliant turn of speed.

Royal Descent is equal second pick at $6 as she steps into weight-for-age company for the first time in a career that went to a new level with her 10-length Australian Oaks win for Rawiller last season.

Rawiller is impressed by what he sees in the four-year-old version of Royal Descent after her placings in the Toy Show Quality and the Tramway Stakes.

He missed the Tramway ride because of suspension and with Glyn Schofield warming his seat, Royal Descent made a sweeping run into a minor placing in a leader-dominated race.

"She feels like she has come back a lot bigger and stronger and that she'll take the next step from three-year-olds to open company," Rawiller said.

"I felt right from the day she won the Oaks that she could go on and be a tremendous Caulfield Cup chance."

While his insight into her future prospects will please Waller and owner Gerry Harvey, it comes with a large dose of reality for the heavyweight rider.

Royal Descent has been given 52.5kg in next month's Caulfield Cup, a weight that is nowhere near Rawiller's range.

"The way she is going I'll just be happy to keep on her for as long as I can," Rawiller said.

In a mirror image of their positions in George Main betting, Hawkspur heads Caulfield Cup markets at $6 from Royal Descent at $10.

Waller will also put the saddle on Shoot Out for the mile specialist's attempt at successive George Main wins.