Dwayne Dunn has won five races on Chautauqua but he is yet to land a Group One on the star sprinter.

He hopes that will change on Saturday.

Dunn was forced to sit out Chautauqua's barnstorming Group One Manikato Stakes win at Moonee Valley last start because of a careless riding suspension.

Tommy Berry partnered Chautauqua to his second Group One win having also picked up the mount on the sprinter when he won the $2.5 million TJ Smith Stakes in Sydney in the autumn.

Chautauqua is the $1.60 favourite for Saturday's Darley Classic as he attempts to go one better than a year ago when Terravista beat him home in the 1200m straight-track race.

Dunn's five wins on Chautauqua have all been in Group races.

His two Group One rides on the gelding have yielded a brace of seconds in the 2014 Darley Classic and this year's Newmarket Handicap.

The jockey said he found it tough to watch the Manikato Stakes but was pleased for the horse and his connections.

"It wasn't his or the connections' fault. I was the one to blame for not being on him, but it's always tough," Dunn said.

"That's the level we want to ride at and compete at, it was disappointing to miss it.

"I've done a lot with him and it would be enjoyable if I could make amends."

The Flemington track was downgraded to heavy during the Oaks meeting on Thursday with more rain expected on Friday.

But it is track bias, rather than the track rating, that Dunn is more concerned about.

The track appeared to favour horses racing on the inside section on the first two days of the Melbourne Cup carnival.

"He's been on rain-affected before and won or placed so he's ticked that box," Dunn said.

"But this track has been a bit different to most of them. It will be interesting come that race what the pattern of the day is going to be.

"He should be hard to beat. Hopefully he gets the job done and onwards and upwards."