Chris Waller has pulled off another Group One training coup with Toffee Tongue breaking her maiden in style in the Australasian Oaks at Morphettville.

The filly had been runner-up at her four starts leading into Saturday's Adelaide feature, twice to Colette in the Adrian Knox Stakes (2000m) and the Australian Oaks (2400m).

Her victory was also a milestone for jockey Damien Thornton who recorded his first win at the highest level after running second in the same 2000m-race on Sheezdashing two years ago.

Although she went into the race a maiden, punters recognised her class and sent Toffee Tongue out the $5 favourite and she delivered by three-quarters of a length over Moonlight Maid ($11).

Waller said the original intention had been to send Toffee Tongue to Queensland but the Oaks in Brisbane has been cancelled as part of a reduced winter carnival impacted by the coronavirus crisis.

"We only decided to send her to Adelaide after she ran so well in the Australian Oaks and the Adrian Knox before that," Waller said.

"She was earmarked for Queensland.

"Even though it was her first win, I felt she was always improving.

"Her run in the Adrian Knox Stakes was great and her run in the Australian Oaks was brilliant.

"She perhaps should have finished at least a bit closer.

"It's great to get the Group One with her."

Thornton had Toffee Tongue well positioned on the fence and stuck to the inside in the run home with Moonlight Maid making her run late.

Affair To Remember ($6.50) was wider and closed late to finish on the heels of Moonlight Miad.

With biosecurity protocols in place regarding interstate travel, Waller said although neither he nor any of his staff could go to Adelaide with the filly, he had the next best thing.

"Andrew Clarken worked for me for about ten years and he has taken out his own licence in Adelaide so I was able to send the horses to him and it was like they were being looked after by our own staff," he said.

Waller, who won the Australasian Oaks three years ago with Egg Tart, said he expected the Jonathan Munz-owned Toffee Tongue to be a force again in her next preparation and would again step up to longer distances.

"She has got the breeding to be a really good horse," he said.

"She is a sister to Werther, a Hong Kong horse of the year and a Hong Kong Derby winner.

"It was 2000 metres today but 2400 metres is certainly not a negative."