John Crowley was left wondering what might have been after Nettoyer scored a runaway win at Randwick on Saturday.

The Sydney veterinarian co-owns the impressive three-year-old filly and he watched in awe as Nettoyer blitzed her opposition on a wet track in the Heard Agency Handicap.

Nettoyer ($13) powered clear under apprentice Rachel King to score by 10 lengths from $4.20 favourite Prometheus.

She was only running in Sydney because she didn't make the Group Two Queensland Guineas (1600m) field at Doomben.

After a recording a winning margin of that magnitude Crowley said: "We'd have given the Guineas a good go."

Instead Nettoyer, a $20,000 yearling purchase, might have to make the jump to black-type in spring with Crowley unsure of her next move.

Crowley said Nettoyer was trained for the Queensland Oaks so he had no fears about the 2000m.

"You can see why she's raced out of her class. We thought she was pretty good," he said.

King, who followed up her first Sydney double at Rosehill last week with another double, was also impressed.

"She relished every yard of it, hopefully she's going to progress a bit further."