Gai Waterhouse's impressive strike-rate continued in Melbourne when she followed up Saturday's Group One double in Sydney by winning the Group Two Gilgai Stakes at Flemington.

Her mare Hallowell Belle ($7.50) collected the sprint event when she edged out King's Rose ($9.50) by three-quarters of a length.

It was a first-up win for the four-year-old who hadn't raced since a Randwick placing on April 28.

Waterhouse collected both The Metropolitan and the Epsom Handicap at Randwick on Saturday.

Her stable representative Dave Meijer said at Flemington that Waterhouse was now likely to select a Group One test next for Hallowell Belle.

"Full credit to Gai ... picking these races for these horses," Meijer said.

"She's really clicked with the fillies and mares of late.

"She's got More Joyous, we've had Tuesday Joy in recent years and the list goes on.

"The world's her oyster now. We've got those 1400 metre fillies and mares races and we can go to a Group One with her now," he said.

Hallowell Belle could now be set for the Group One Myer Classic (1600m) at Flemington on November 3, although Meijer would not confirm an entry.

"I'll leave that one to the boss," he said.