Matt Cumani has wasted little time in starting to make an impression in Melbourne racing, celebrating his first city winner as a trainer.

Cumani had his first runner on April 1 after setting up at Ballarat in Victoria, and Show A Star's victory in Saturday's Peter Jackson Handicap at Caulfield was a milestone the 35-year-old said had come sooner than expected.

The trainer's first winner was at Bendigo eight days ago and he had another at Cranbourne on Friday night before Show A Star's win as the $5 favourite.

"Hopefully it's a sign of things to come," Cumani said.

"I thought it might take me a bit longer to get a Saturday winner at Caulfield, but I'll take it.

"For me it's a big milestone. And I hope they will be common in the future but for now it feels like a huge step from where I have been even just a few days ago, a few weeks ago and six months ago.

"It's fantastic and hopefully we can keep the ball rolling."

Cumani is the son of prominent UK-based trainer Luca Cumani, and brother of racing media identity Francesca Cumani.

Ridden by apprentice Jordan Childs, Show A Star sat off the leader Airalign before hitting the front inside the final 150m.

He defeated Leonforte by a ha;f length with 1-1/4 lengths to Airalign.