There was a time when Chris Waller thought winning the greys-only race at Flemington during Melbourne Cup week would be the pinnacle of Arinosa's career.

He has now been forced to reassess her as a potential Group One horse after her explosive 4-1/4 length win in Saturday's Group Two Sapphire Stakes (1200m) at Randwick, her fourth victory in succession.

"Confidence does great things for horses, for sportspeople and people in general," Waller said.

"She's taking on better horses and still winning.

"Timing-wise we've probably left our run a bit too late for Sydney, so we'll probably give her a week or two in the paddock and get ready for the Tatt's Tiara in Queensland.

"Hopefully that's her chance for a Group One."

Waller also flagged the possibility of a start in the All-Aged Stakes at Randwick in two weeks, but said the Brisbane carnival was more likely.

Jockey Brenton Avdulla was gobsmacked by the manner of Arinosa's win.

"It's just shocking how well she keeps going and stepping up to the mark," he said.

Miss Stellabelle did best of the chasers to grab second, with Forarainyday another head back third.