The spring destination for Blue Diamond Stakes winner Earthquake will depend on how she races over an uncharted distance at Randwick on Saturday.

In what has been identified as a crossroads race for the Godolphin filly, Earthquake lines up for a return clash against Winx in the Tea Rose Stakes.

And while Winx clearly had the better of Earthquake when they met on soft ground in the Furious Stakes, the outward signs are promising about a different result on a better track.

"Her coat has come through, you will see an improvement in that," Godolphin racing manager Jason Walsh said.

"She didn't winter too well. She's had a long, wintry coat and she hadn't started to hold her condition properly until the last month or so."

It is what is inside Earthquake's frame that has trainer John O'Shea and jockey Kerrin McEvoy second guessing her immediate future and the Tea Rose will definitely shape the rest of the filly's campaign.

She will be stretched beyond 1200m for the first time on Saturday and Walsh says there is a reluctance in the Godolphin team to make a call on Earthquake extending her brilliance to 1400m.

"We're all sitting on the fence getting splinters," he said.

"We're progressing with a degree of trepidation but I think she will because class usually prevails against their own age and sex."

If Walsh is right, Earthquake can be expected to head to Melbourne for her next start over 1600m.

Otherwise, she will be given her chance against the colts in a Group One sprint for three-year-olds on the first day of the Melbourne Cup carnival.

"If we feel she is strong to the line at seven (furlongs) we'll continue to the Thousand Guineas because she's got a great record at Caulfield," Walsh said.

"But if we think she is suspect at seven we'll freshen her up and aim her at the Coolmore Stud Stakes."