James McDonald has ridden his 100th Sydney metropolitan winner for the season on the anniversary of his comeback to the saddle after a ban for betting.

Capping an almost seamless return since rebooting his career at the corresponding Warwick Farm meeting last year, McDonald brought up his milestone on the John Thompson-trained Primitivo.

In reaching his century, McDonald became the first jockey since Darren Beadman in 2006-07 to ride 100 Sydney winners in a season.

Beadman rode a record 164 winners that season, his last in Sydney before leaving for Hong Kong.

Primitivo won narrowly with ex-pat kiwi McDonald praising his mount's courage.

"I would have rather have brought my one hundred with a bit more of a margin but, anyway, a win's a win so it's a good result," McDonald said.

"It's been a wonderful year, a very fast year."

McDonald has ridden six Group One winners this season, putting him second to Hugh Bowman for elite-level victories.

As Bowman takes a break from racing, McDonald is assured of winning the Sydney jockeys' premiership for the third time.