One-time Queensland Oaks prospect Firebird Flyer has made it back-to-back wins in Sydney.

While the filly didn't develop in time to travel north for the Oaks, the Chris Waller-trained Firebird Flyer ($8.50) claimed the biggest win of her career on Saturday when she edged out Storm System ($7.50) by a nose in The Mick Crusher Kerr Memorial at Randwick.

Having her sixth start for the preparation which has included two wins and four seconds, Firebird Flyer's fitness shone through over 2000m on a heavy track.

Waller said he had plenty of fears about how she would handle the going, but her toughness allowed her to overcome the wet surface.

"She's a fit horse," Waller said.

"She's been up such a long time. They're the kinds of horses that fight."

A last-start winner in a 1600m-Warwick Farm maiden, Firebird Flyer handled the step up in distance and class to score consecutive wins.

"It might not have been by much, but it makes no difference to the pay cheque," Waller said.

Sydney prize money is precisely why Firebird Flyer's New Zealand owners sent her to Waller's stable, and she picked up more than $48,000 for her win on Saturday.

Waller praised Tim Clark's patient ride after the filly came from second-last to win.

"He didn't panic. He just held it together nicely," Waller said.