Winona Costin has announced her arrival in Sydney's senior jockey ranks by riding a winner at her first race meeting since finishing her apprenticeship.

Costin opened her account aboard the Greg Hickman-trained Centro Superior in a 1200m benchmark handicap at Warwick Farm on Wednesday.

"First day of being a senior rider and I get a winner so it's fantastic," Costin said.

"It's very good to get it for a good supporter of mine in Greg Hickman."

Costin had a tough final year of her apprenticeship, battling injuries which kept her out of the saddle for three months.

Those lay-offs prevented the lightweight rider from defending her Sydney apprentices' premiership, but she still managed to finish fourth in the junior ranks by riding 18 winners for the season.

Costin said Centro Superior's win was a good confidence boost as she kicks off the new season.

"I've just got to keep doing the same things I'm doing and see how it pans out," she said.

"My confidence has been a bit low of late but it's picking up now."