Bruce Wallace insists he can't take too much credit for his only Chipping Norton Stakes win.

And the New Zealand trainer already seems happy to deflect any praise which might come his way should he make it a second in the Group One weight-for-age race with King Mufhasa at Warwick Farm on Saturday.

It's been 20 years since Wallace successfully saddled up Kingston Bay as an inexperienced three-year-old with hardly a dollar of prize money to his name against a field of stars.

"Kingston Bay ran second in the Hobartville Stakes and then (Randwick trainers) Jimmy and Greg Lee actually talked me into running him a week later in the Chipping Norton," Wallace said.

"They said if I did I wouldn't have to worry about galloping him during the week."

But Wallace says he started to regret his decision as the runners were being loaded into the starting stalls.

"They said twenty million something dollars in stakes this field has won and I looked down at my racebook and saw Kingston Bay with seventeen thousand dollars," Wallace said.

"And I think ten or eleven thousand of that he had won the week before. I thought ... what the hell am I doing in this race."

There promises to be much less second-guessing with King Mufhasa despite the veteran front-runner only finding his way into Wallace's stable a few weeks ago.

"I haven't had him long but he's a good old horse," Wallace said.

"He travels and after he went from Melbourne to Sydney on the float he hasn't left an oat."

King Mufhasa won 10 Group One races under Stephen McKee and the old-timer's obvious race craft ensures Wallace has a manage rather than nurture the horse's talents.

"He's got his issues ... he gets a bit arthritic but he's a real racehorse," Wallace said.

King Mufhasa is a $12 chance in a race - traditionally the first Group One of the Sydney autumn carnival - which has been dominated by horses trained by Gai Waterhouse and Chris Waller for the best part of a decade.

Last year' winner, the Waller-trained Shoot Out, is sharing favouritism with Manighar at $5.

Track manager Mark Jones said Warwick Farm was rated in the dead range on Friday morning but forecast showers could put any upgrade in doubt.

"The track is improving all the time but we'll have to see what tomorrow brings," he said.