As he followed Sea Siren off the training track at Sha Tin on Thursday, John O'Shea could barely hold himself back to a brisk canter.

And an hour-or-so later when the mare drew ideally in barrier seven for Sunday's $HK15 million Hong Kong Sprint (1200m), the trainer almost broke into a gallop.

"That's just what we wanted, it's beautiful," O'Shea said.

Sea Siren performed a similarly attractive piece of work to prepare for what it is hoped will be her fourth Group One victory on Sunday in a race that has been almost totally dominated by locals since the Queenslander Falvelon scored the second of his two wins in the event in 2001.

Only the South African JJ The Jet Plane, who won in 2010, has interrupted the locals who have won 10 of the past 11 runnings.

But Sea Siren is regarded by keen form students in Hong Kong as the best Australian-trained prospect in a decade.

Sea Siren galloped on the course proper at Sha Tin on Thursday, having had an easier time in boggy conditions the previous day.

"I was very pleased with her this morning," O'Shea said.

"I didn't ask her to do much on Wednesday and on Tuesday she was a bit fresh and wanted to rip and tear.

"Today she was much more relaxed.

"I only wanted her to stretch her legs, not break any records."

O'Shea was nevertheless keen to get back to the barn to check the mare over after her work.

"She's very well, I just want to get back there and make sure."

Australia's second representative on the international program, Alcopop, also followed an impressive workout with a perfect draw, coming up with barrier four in the Group One $HK22 million Hong Kong Cup (2000m).

Trainer Jake Stephens reported the Mackinnon Stakes winner to be "completely over" the issues that caused him to lose weight soon after his arrival and the horse turned out in good order to work on the all-weather track on Thursday.

Like O'Shea, Stephens appreciates the enormity of the task confronting Alcopop whose opposition includes the world's highest-ranked racehorse, Cirrus Des Aigles, but believes the horse has acquitted himself well against good class opposition already this preparation.

"This is a fantastic experience for me and for the horse," he said.

"He'll run the best race he can, I'm sure of it."

As well as Cirrus Des Aigles who drew alongside him in five, Alcopop will be opposed by local star and defending Cup champion California Memory who ran one of the best races of his career last start in the Cup trial, overcoming a chequered passage to beat Irian who is also in Sunday's line-up.