Young Melbourne jockey Patrick Moloney has never ridden in Sydney.

That will change on Saturday when the 22-year-old from a famous racing family rides in one of Australia's biggest races at Randwick.

Moloney, the grandson of the late Hall of Fame trainer Jim Moloney, has ridden in eight Group One races in Melbourne and one in Adelaide.

Just out of his apprenticeship, Moloney will have a chance to make the best possible start to his senior career when he rides He Or She in the $3 million Doncaster Mile.

Last season's champion Melbourne apprentice is a natural lightweight and will ride the David Hayes and Tom Dabernig-trained He Or She at 50kg.

He usually walks around at around 52kg, but Moloney has increased his cardio workouts to be fit and strong at the lower weight.

"I have done it before and did it only a couple of weeks ago to ride Keen Array in the Newmarket Handicap," Moloney said.

"I know I can ride the weight really strong."

He Or She appreciated a fast tempo when he beat subsequent Group One winner The United States to win the Group Two Blamey Stakes.

While he accepts Winx will be hard to beat, Moloney believes He Or She can be in the finish.

"I'm sure He Or She is in tip-top shape and I couldn't see why he couldn't run a really cheeky race," he said.

Having achieved the goal to outride his claim as a junior rider, Moloney is keen to take the next step in his senior career.

"I have won a Group Two and a Group Three, so the next goal is definitely to get that Group One," Moloney said.