Sea Siren did enough in her first visit to Moonee Valley to convince trainer John O'Shea the mare will be a force to be reckoned with in the Manikato Stakes.

O'Shea took Sea Siren to Moonee Valley for Tuesday morning's Breakfast with the Best trackwork session ahead of Friday night's Manikato Stakes (1200m).

Sea Siren is among 10 acceptors for the Group One sprint, which will be run on Cox Plate eve for the first time.

"I think in my experience with them they either handle it (the Moonee Valley circuit) the first time or it's just a waste of time," O'Shea said.

"The first time we brought Racing To Win here he was a disaster and of course it (the 2006 Cox Plate) was a disaster.

"I brought Foxwedge here and galloped him and he was brilliant. Then in his first crack here he raced well.

"She has come here this morning for the first time and Jimmy (Cassidy) was happy with her capacity to get around it so I don't see it being a problem."

Racing To Win was a well-beaten favourite in the 2006 Cox Plate while Foxwedge won the Group One William Reid Stakes at the track in March.

O'Shea said Sea Siren was where he and the mare's jockey Cassidy wanted her for the first-up assignment.

"Jimmy was happy enough with her work this morning and if Jimmy is happy, I'm happy," O'Shea said.

O'Shea said the dual Group One winner had strengthened with her spell after a successful Brisbane winter campaign and was set to race about 10kg heavier than before.

Star Queensland sprinter Buffering is a clear-cut favourite for the Manikato Stakes as he chases his first Group One success.

Buffering won the Moir Stakes at Moonee Valley under lights first-up and worked with stablemate Excellantes at the track on Tuesday.

He has drawn the inside barrier for the Manikato with joint second favourites Sea Siren and Lone Rock to jump from gates five and eight respectively.

The Peter Snowden-trained Mental resumes in the Manikato from barrier nine while last-start Group One Sir Rupert Clarke Stakes runner-up We're Gonna Rock has the outside gate.