The $3.5 million Golden Slipper appears to be at Earthquake's mercy with trainer Peter Snowden adamant she is yet to peak despite extending her unbeaten run at Rosehill on Saturday.

Racing for the first time since her Blue Diamond Stakes win in February, Earthquake didn't appear comfortable leading from an outside draw but she showed her quality to pull away from Mossfun in a Reisling Stakes victory more professional than spectacular.

"To me, she hasn't peaked," Snowden said.

"This filly, she hasn't blossomed into that fit horse yet.

"Fresh like that, to go and lead all the way like she did with fit horses and beat them well. It shows you what sort of talent she's got."

Sepoy claimed the Blue Diamond Stakes-Golden Slipper double for Snowden in 2011 and the Darley trainer maintains he is the best two-year-old he has prepared.

A Golden Slipper victory by Earthquake could prompt a reassessment.

"Sepoy's the best. He's as good as I ever had at Crown Lodge. But she's getting up there."

Snowden also produced Todman Stakes winner Ghibellines but said Earthquake was in a different class to the colt.

"Earthquake and Ghibellines, there's a fair space between them," he said.

Earthquake started a $1.45 favourite, ahead of the previously undefeated Mossfun ($4.80) who raced outside the Darley filly.

But when Kerrin McEvoy asked for an effort Earthquake shook off Mossfun and despite drifting out under pressure scored by 1-1/4 lengths over the Hawkes Racing filly.

"She towed me forward today, she was a bit fresh and going to the front was the only option to get her to relax," McEvoy said.

"She cruised into that spot and she's got the goods to be able to do that."

Alpha Miss ($26) ran her usual honest race for third another half-length away.

Earthquake has firmed to $2.10 favouritism for the Golden Slipper ahead of Mossfun at $6.50 with the Todman quinella of Ghibellines and Unencumbered $13 apiece.