There have been better Group One races than the All Aged Stakes during the Sydney carnival, leaving trainer Grahame Begg certain he has made the right call for Bennetta.

Bennetta is one of the outsiders in the $400,000 weight-for-age race at Randwick on Saturday but a small field reduced even further in size because of scratchings has confirmed Begg's suspicions.

"If you are going to have a go at a Group One race it's probably the one because it has fallen away a bit," he said.

"That was always in the back of my mind."

Nevertheless, five of the nine runners are Group One winners and Begg isn't getting ahead of himself with a mare who hasn't won a race since she was a filly when she claimed the Light Fingers Stakes almost 15 months ago.

Bennetta was also entered for the Hall Mark Stakes but Begg insists the timing is right to chase something more significant.

"It's more about getting the Group One for the breeding side of it for the owner, George Altomonte. Even a Group One placing," Begg said.

"But we are under no illusions. She has got to step up to the mark."

Bennetta was rated a star in the making in the early part of 2013 but her five starts as a four-year-old have returned only two minor placings.

But for a stable down on its luck this season, Bennetta provided a timely sign that improved results were not far away when she resumed with a solid third over 1200m on a rain-affected track at Rosehill on April 5.

"I thought her run on Golden Slipper day was very good but with another heavy track last week we decided to miss the Sapphire Stakes," Begg said.

"She was either going to back up in the All Aged or go straight into the race so the plans are still the same."

Bennetta is a $19 chance in updated All Aged betting after Snitzerland and Politeness were scratched on Thurdsay.

But in a positive lead for Begg, James McDonald, the jockey who has ridden Bennetta in all three of her wins, stays true to the cause on Saturday.

McDonald is leading the race in the Australian Turf Club's Golden Whip award for the most successful rider during the six weeks of the Sydney autumn carnival.