Trainer Gai Waterhouse was at her persuasive best before Carriages took out the Magic Millions Clockwise Classic at Ballarat.

Waterhouse "nagged" owner David Henderson into sending Carriages down from Sydney for the one-off race at Ballarat, restricted to graduates of Magic Millions sales.

It took until last Saturday before Henderson relented and agreed to send the filly to Victoria for the $200,000 race.

The victory now cements the daughter of Hinchinbrook a start in the Magic Millions Classic at the Gold Coast on January 10.

Waterhouse was proven correct again as Carriages scored by two lengths from the favourite, the unbeaten Danny O'Brien trained Prompt Return.

Carriages had the experience of racing right-handed, finishing third behind Mine Two at Randwick on November 8, an effort that left Henderson feeling deflated.

"Two weeks ago I went to the races and I thought she would just win and honestly I was flattened when she ran third," Henderson said.

"She had worked tremendous, trialled tremendous and was going absolutely great guns and I scratched my head and lost a bit of confidence.

"Gai pumped us up again and we've come down here and she's got the job done and beaten a pretty smart horse."

Williams said he spoke to Waterhouse on his way to Sandown races last week and was told not to take a ride in the Ballarat race before again speaking to her on the way home.

"She's got really good gate speed and that is what won her the race," Williams said.

"The intention was to make the most of our experience going right-handed and we did that today."