A wet Rosehill track has brought a betting plunge unstuck with outsider Mrs Madrid showing the ability her trainer has always been confident she possessed in an upset result.

Anthony Cummings sent Mrs Madrid to Saturday's 2000m-race as a $26 chance with the imported Heart Of Grace backed from $34 early this week to $3 favouritism.

When the going got tough, Heart Of Grace was nowhere to be found with Mrs Madrid in control and holding off New Zealand visitor The Good Fight ($14) by a half length.

Heart Of Grace, who was sourced from Europe by clients of Perth trainer Frank Pangallo finished 70 lengths from the winner.

Cummings had tried to get Mrs Madrid to the Queensland Oaks but she did not have enough prize money to get in the race.

"She had the benefit of fitness from her Brisbane campaign," Cummings said.

"And she plainly likes the wet.

"I told Glen (Boss) to have her where she was comfortable and left it up to him.

"I tried her in nice races last time through but she was always a week behind.

"She ran second one day at Warwick Farm and that was costly because she missed the Oaks because of a lack of money.

"But now we can look at better races."

Cummings has a depth of talent in his spring stable with Libertini and Mizzy, both winners last Saturday, and Boss is rebuilding his career in Australia after relocating to Sydney from Singapore.

He was also impressed with her win and said there was more in the tank.

"They went very quick. It was a sustained gallop the whole way," he said.

"I think there's still a bit of improvement in her too."

Heart Of Grace's jockey Brenton Avdulla said the mare failed to handle the heavy track.

"She struggled in the ground," he said.