The transformation in Just As Cosmic has convinced trainer Steven Wilson he made the right call to pay a late entry fee to run her in Saturday's Queensland Oaks.

After Just As Cosmic finished fifth to Dear Demi in The Roses at Doomben on May 18, Wilson recommended the filly's owners part with an $11,000 late-entry fee for the Oaks at Eagle Farm.

"That was her first run over 2000 metres and it's really toughened her up and brought her on a bit more," Wilson said.

"Since that race she looks a lot better, she's a lot fitter, there are dapples all over her and she's bright in the coat.

"She's certainly gone forwards, not backwards."

With a stable of six horses at Rosehill, Wilson will have his first Group One runner when Just As Cosmic contests the Oaks.

The filly settled near the rear of the field in The Roses but Wilson believes she can race closer in the Oaks.

"We'll probably go forward and see if we can get into a spot hopefully midfield then peel to the outside and have one good crack at them," Wilson said.

Although Just As Cosmic will start from barrier 14, Wilson believes the prospect of wet track will be to her advantage.

"By that stage of the day she'll probably be better off coming down the outside where the going will be better than close to the fence," he said.

Eagle Farm is rated a slow 7 after 27mm of rain on Thursday afternoon.

The Gai Waterhouse stable is confident Porcellanus can make the jump from midweek company to Group One success at only her third start in a race.

"Even though she's coming off a mile win at Warwick Farm she did beat older mares," stable foreman Mark Newnham said.

"Gai's record of stepping horses up in distance is second-to-none and this filly is bred to handle it."

Miss Keepsake (2010), Zagalia (2003) and Mon Mekki (2002) were successful in the Oaks after racing in midweek company at their previous starts.