Hong Kong's premier jockey Zac Purton was the beneficiary of some family advice before winning on Strawberry Boy at Doomben on Saturday.

Purton is no stranger to Doomben and won the Brisbane jockeys' premiership in 2002-03 before heading to Sydney and then Hong Kong.

Strawberry Boy ($4) led all the way to beat Lucky Lago ($9) by 2-1/2 lengths in the Group Three Lord Mayor's Cup.

Purton's father-in-law Jim Cassidy has ridden Strawberry Boy several times including his last-start when sixth in the Scone Cup last week.

Trainer Chris Waller said it had been an easy decision to replace Cassidy with Purton.

"Jim decided to ride in Sydney so I kept it in the family. Jim had a chat to Zac about how to ride Strawberry Boy and he obviously listened," Waller said.

Purton has swept all before him in Hong Kong, being last season's premier jockey and he has also been a major player at other Asian centres.

He won the Group One KrisFlyer International Sprint on Aerovelocity in Singapore last Sunday.

However, Purton also took the chance to have a light-hearted shot at his arch-rival Joe Moreira, the Hong Kong-based jockey who rode for Waller during the autumn carnival.

"Chris is a quick learner. He used Joe Moreira during the autumn and got nothing. He puts me on and we get a win," Purton joked.

Waller said Strawberry Boy would remain in Queensland.

"I don't think he really gets further than 1600 metres. He puts everything into his races and 1600 metres is about as far as he wants to go," he said.

Waller said Strawberry Boy was a tough horse who had done a lot of travelling in the past eight days.

"He went from Sydney to Scone and then back. He then went to the Gold Coast and up here for today's race," he said.