James McDonald gets a chance to showcase his versatility when he partners New Zealander Who Shot Thebarman in Saturday's Sydney Cup at Randwick.

McDonald produced a masterful, quick-thinking ride to win the Golden Slipper over 1200 metres last month but Saturday's race will be at the other end of the distance spectrum.

The 3200-metre marathon is set to be a true test of stamina with the race almost certain to be held on a slow or heavy track.

Those conditions won't worry Who Shot Thebarman who is proven in all types of ground.

Nor is he a query at the distance having captured the Auckland Cup last start.

In fact, the only concern McDonald has about the horse's Sydney Cup credentials is his inexperience.

Who Shot Thebarman has raced just nine times and McDonald admits that could come against him when he takes on tough, seasoned stayers in a high-pressure race.

"He's very raw which is a little bit of a worry, especially competing on a bigger stage," McDonald said.

"But geez, he gives you a feel."

A field of 17 will line up in the Sydney Cup headed by former Dermot Weld-trained mare Voleuse de Coeurs who is now with Mike Moroney.

The Offer is a firm favourite after successive wet track wins and will be striving to give Gai Waterhouse another feature 3200-metre victory this season after Fiorente's Melbourne Cup triumph.

Who Shot Thebarman is trained by Mark Oulaghan, little-known in Australia but a man in whom McDonald has great faith.

"He wouldn't bring him over if he didn't think the horse was up to it," McDonald said.

"His record speaks for itself. He's very good with jumpers and with stayers and obviously you have to be a very good trainer to train those horses."