Punters have been left nursing their wounds after White Moss turned in a stunning all-the-way win in the Group Two Millie Fox Stakes at Rosehill but her trainer Jason Coyle was less surprised than most.

The striking grey was sent out at $51 in Saturday's 1300m-race for mares and under controlled riding from Kathy O'Hara held off well-supported favourite I Am Serious ($2.80) by a long head.

After her unplaced effort in the Breeders Classic at Warwick Farm when she bungled the start, Coyle fitted her with a barrier blanket to help avoid a repeat.

"I think the barrier blanket helped and she jumped well today," Coyle said.

"Before her last start, her barrier trials were good so she wasn't going badly."

Coyle and her owners, the Esplin family, are now eyeing off the Group One Coolmore Classic with Coyle confident she can stretch to 1500 metres.

"That is the logical next step and she should get in with a light weight" he said.

Many of the mares she raced against in the Breeders and the Millie Fox will again be her rivals in the Coolmore Classic.

O'Hara, who won the race in 2012 on Ofcourseican, was not aboard at Warwick Farm but has had several rides on White Moss.

"She was able to get free-striding once she got to the front," she said.

"She is very tough and gives 100 per cent."