Two fillies with Group One aspirations have posted important midweek wins at Randwick on their way to carnival racing.

A change of tactics and distance gave Amanpour an overdue win and confirmed trainer Gai Waterhouse's belief she has an Oaks filly on her hands.

The Bart and James Cummings-trained Brook Road, who is among entries for the Australian Guineas, came from behind in her 1150m race to score impressively.

Tommy Berry jumped Amanpour ($6) straight to the front in Wednesday's 1800m race for three-year-olds opened up a lead of between six to eight lengths mid-race.

The filly showed no signs of tiring and held her position to beat Into The Groove ($19) by 6-3/4 lengths with Falago ($6) a long neck third.

Waterhouse's representative Mark Newnham said the trainer had taken stock of the filly's manners and results at her first six starts up to 1400m and decided the sprints weren't for her.

"Gai always thought she could stay and altered her work accordingly," Newnham said.

"She will be entered for the Oaks and now Gai will look at the best path to get there.

"There are races like the Keith Nolan and the Storm Queen on the way.

"She will certainly get 2000 metres on that performance and there's no reason she won't get 2400.

"She has always had the ability but was frustrating over shorter trips and racing well without winning."

The Australian Guineas at Flemington on March 1 might come around too soon for Brook Road whose next start is likely to be the Light Fingers Stakes (1200m) at Randwick on Saturday week.

The filly came out of the pack to charge home and beat her older rival Southern Girl by 1-3/4 lengths in the 1150m race on the program.

"I will defer to my more experienced partner on where she goes. Bart will make the decision," James Cummings said.

"She is entered for the Australian Guineas but it would be tight.

"There are options for her in Sydney with a lot of nice fillies races coming up."