Under-rated mare Appearance has backed up her surprise Group One triumph from the spring with a thrilling Coolmore Classic victory at Rosehill on Saturday.

In a three-way finish that had many unsure who had won, the Guy Walter-trained Appearance ($11) arrived just in time in a driving finish to beat brave mare Red Tracer ($26) by a nose with classy filly Norzita ($7.50) the same margin away third.

The win was a moment to savour for jockey Blake Shinn who notched his first Group One success since his return from a 12-month disqualification more than a year ago for betting offences.

Walter was caught off guard when Appearance won the Myer Classic in the spring but had nothing but praise for the Darley-owned mare after she proved that victory was no fluke.

"This is a very under-rated mare, I don't think she has got enough credit," Walter said.

"I said after the Myer Classic that she got under the radar, I didn't think she could win that day, and here we are again.

"She's only had 12 starts and has won two Group Ones plus a Keith Nolan Classic. This is just an outstanding mare."

Peter Snowden is the head trainer for Darley Australia but Walter always has several fillies and mares in training for Sheikh Mohammed.

"They've been tremendous supporters of mine over a number of years," Walter said.

Henry Plumptre, head of Darley Australia, returned the compliment, saying Walter had been able to get the best out of the daughter of Commands.

"She's the perfect filly for Guy," Plumptre said.

"She's difficult to train and he's done a great job and been patient with her."

In a race where in-form mare Steps In Time worked across from an outside gate to take up the running, Shinn had Appearance just better than midfield and ready to strike.

Red Tracer, who had 57.5kg, peeled off the leader's back inside the final 200m and looked the likely winner after hitting the front with 150m to run.

But Appearance found plenty for Shinn and dived through inside Norzita who stormed home out wide.

"She has to be the best three-year-old filly in Australia after that," James Cummings said of the Bart Cummings-trained Norzita.

For premier trainer Chris Waller, who prepares Red Tracer, he was denied a Group One double on the day by the barest of margins.

"That was breathtaking," Waller said.

"She ran super and is a Group One horse, simple as that. She just hasn't managed to get one yet."

All three placegetters will meet again under weight-for-age conditions in two weeks in the Queen Of The Turf Stakes over the same course and distance.