Jockey Michael Walker has guided staying mare Fanatic to victory in the Listed Sandown Cup before being ruled out for the rest of the meeting due to illness.

Walker was replaced on his final two rides at Saturday's Sandown meeting after struggling physically after the gruelling 3200m race.

Walker said post-race he had been told the previous day by a doctor he's got pneumonia and that he "tried to ride through it".

A winner of last year's New Zealand Oaks, Fanatic ($4) is in her first Australian preparation since joining the Lindsay Park stable and she got the better of Swacadelic ($4) over the closing stages to win by a long neck.

The $2.35 favourite Gallic Chieftain was another 1-1/4 lengths away third while Darabad ($18) held on for fourth after opening up a huge lead during the middle stages of the race.

Fantatic's co-trainer David Hayes praised the ride of Walker who won the Sandown Cup on Almoonqith for the stable two years ago.

"She's a mare who doesn't like being exposed too far from home," Hayes said.

"And he (Walker) did it really well.

"I think Michael's got a bit of pneumonia so it was a good tough effort. That's why he's pulled up a bit short, but I'm sure the mare has pulled up well."

The five-year-old's Sandown win came after winning over 2800m at Flemington at her previous start and Hayes will look at the Adelaide Cup next preparation.

"I'll probably look at a race like the Adelaide Cup and then maybe go to Sydney," Hayes said.

"She's a kiwi mare that doesn't like wet tracks."