The Chris Waller-trained Sir Bacchus must overcome the outside barrier and unfamiliar track conditions to justify his joint favouritism for the Winter Dash at Randwick.

The four-year-old also steps back in distance from his last-start second in the Octagonal Handicap at Rosehill earlier this month but Waller's racing manager Charlie Duckworth thinks the barrier will be the toughest obstacle to overcome on Saturday.

"The barrier does make it a bit tricky," Duckworth said.

In January last year Damien Oliver had to navigate Sir Bacchus from the outside gate in the Magic Millions 3YO Guineas on the Gold Coast, and he ran wide throughout to finish 10th in the 16-strong field.

Sir Bacchus, who was alongside the Darren Beadman-trained Tessera on Friday as the $3.20 favourite for the 1200m-race, has been blessed with inside gates during this preparation, never having jumped from further out than barrier four in his three runs.

He also strikes a heavy track for just the second time though Duckworth disregarded his first run on that type of ground, where he finished second last at Randwick in an benchmark race in April.

The course was upgraded on Friday from a heavy 9 to an 8 and Duckworth was confident Sir Bacchus would acquit himself better.

"Despite not looking like a very good run Kerrin (McEvoy) got off and gave a glowing report," Duckworth said.

There were mitigating factors with Sir Bacchus being checked early and then blocked in the straight.

Waller is well represented at Randwick, where stayer Richard Of Yorke ($3.60) backs up from a dogged run in the Stayers Cup (3200m), and three-year-old O'Rachael ($11) makes her Australian debut after crossing the Tasman from Stephen McKee's stable.

Duckworth was encouraged by Richard Of Yorke's run behind Plot Twist and said he had recovered well.

"He's dropping back to the 2400 where his form has been exceptional and he lost nothing in defeat last start," he said.

"He's certainly showed no ill-effects of being flattened by the two mile run."

Duckworth was confident O'Rachael, who raced in Group or Listed company five times in New Zealand, would handle her new environment in a benchmark handicap (1200m).

"She's seemed to have acclimatised to our way of training very well," he said.

"She's got some black-type to her name and should be able to run a very nice race over this trip."