A switch in plans has led to a bigger payday for the owners of Fontein Ruby.

Trainer Robert Smerdon had intended sending Fontein Ruby to Adelaide for a Group Three race but instead kept the filly at Caulfield on Saturday to collect the winner's purse in the Thoroughbred Breeders Victoria VOBIS Gold Reef.

"It was all about going to Adelaide today and I hadn't realised until last weekend that she was eligible for this race," Smerdon said.

"From a pedigree residual point of view she was already a Group Three and a Group Two winner so it's now only a Group One that we're after."

The Caulfield win netted connections $180,000 whereas victory in Adelaide would have been a $73,000 result.

Smerdon said Fontein Ruby would now get her chance at a Group One victory when she heads to Adelaide for the Australasian Oaks (2000m) at Morphettville on May 2.

Fontein Ruby is already a winner over 2000m in the Caulfield Classic last spring but Smerdon said the Morphettville course presented a tougher test.

A $50,000 yearling purchase, Fontein Ruby took her prize money past $1 million on Saturday.

Backed from $2.25 to run the $2.10 favourite, Fontein Ruby led throughout in scoring by 1-3/4 lengths over Jurasound ($3.60) with War Point ($26) three quarters of a length away third.