Craig Williams has resisted the temptation of interstate travel in recent seasons unless he has the chance to add a Group One win to his resume.

The jockey will bypass the chance to increase his lead in the Melbourne jockeys' premiership on Saturday, instead heading to Perth for the Winterbottom Stakes (1200m) at Ascot.

Williams partners the Ciaron Maher and David Eustace-trained Dubious in the $1 million weight-for-age feature, a race he has won twice previously on Ortensia in 2009 and 2011.

"If the right horse comes around, they're still Group One races worth $1 million so it's definitely worth us making the trip over there," Williams said.

Williams, winner of his first Melbourne Cup earlier this year, rides Dubious for the first time on Saturday.

The three-year-old goes into Saturday's race having not raced since finishing sixth behind Anaheed in the Blue Sapphire Stakes (1200m) at Caulfield last month.

Williams does not ride for the stable often but partnered another of its three-year-olds, Loving Gaby, to win the Group One Manikato Stakes at The Valley last month.

"I've worked with Dubious before on the track and been his opposition multiple times," Williams said.

"The stable always say how straightforward and professional he is.

"The barrier (5) looks good and he hasn't had a long spring that some others may have had.

"He fits the criteria well and I think he's drawn nicely to get every opportunity."

Lining up for his 11th start on Saturday, Dubious is a seasoned traveller having raced in Sydney, Brisbane and Melbourne, registering victories at Randwick, Doomben and Eagle Farm.

"He looks like a horse that loves to travel," Williams said.

"I remember when I was riding in Europe some horses raced better away from England and this horse looks like he races well away from home.

"I'm hoping that will be the case with on Saturday."

Dubious is a $14 chance in latest markets with Godolphin's Trekking the $2.50 favourite ahead of local Perth hopes Vital Silver and Stageman at $8.50.