Apprentice Josh Cartwright has landed his first Melbourne winner on a filly who has also posted a breakthrough city success.

The Robbie Griffiths-trained Romancingthestone powered to victory in the opening race at Caulfield on Saturday, giving 19-year-old Cartwright his first Melbourne winner having previously claimed a city win in Adelaide.

Romancingthestone was sent out the $3.80 favourite in the Claire Andrews Handicap (1000m) and after enjoying an ideal, run sprinted clear to defeat Mitza Del Bra ($6) by 2-1/4 lengths with a head to I Got A Turbo ($7.50) third.

Cartwright, who is apprenticed to Jamie Edwards and Bruce Elkington, has been riding in races for two and a half years and had booted home 96 winners before landing Saturday's Caulfield success.

He said it was a big thrill and thanked Griffiths for the opportunity.

"Robbie has supported me from day one in town. I finally got my winner for him in town and I'm very happy," Cartwright said.

"It's hard to get on good horses like this. And today when I got such a nice run she quickened so well for me."

Romancingthestone brought up her second win from 12 starts having won a maiden at Geelong, but the three-year-old has placed another six times in town including twice in Listed company.

"This filly deserves the win," stable representative Don Healy said.