Mick Kent is not convinced promising staying mare Scratchy Bottom has had the ideal preparation for the Chairman's Handicap at Randwick.

But the wet track has boosted the trainer's confidence the mare can can take out Saturday's Group Two race.

Scratchy Bottom's task was made easier on Thursday with the withdrawal of Rising Romance who was showing signs of a virus.

Scratchy Bottom defeated Rising Romance at her last start in the Epona Stakes at Rosehill on March 21, a fortnight after failing to beat a runner home in the Frances Tressady Stakes at Flemington.

"It's a bit of an ask for her going from seven (furlongs) to 1900 and then 2600 metres," Kent said.

"She's only had the one run beyond the mile and a quarter previously and that was in Adelaide in the Derby last year when she got beaten a nose.

"She's done very well. I'm very pleased with her and I'm happy to be there."

Scratchy Bottom's South Australian Derby second, when beaten by Kushadasi over 2500m, was also her only start on a wet track.

Kent takes a lot of heart from that effort although admitting the form from the race has not been strong.

However the daughter of Sebring has also shown a liking for soft ground on the training track.