James McDonald celebrated his return to racing following an 18-month disqualification by heading straight to the winners' stall at Warwick Farm.

The former Sydney premiership-winning jockey guided Cormac to victory in the TAB Handicap (1400m) in his first ride back since being disqualified for betting on his mount Astern in 2016.

McDonald prevailed in a tight battle with Kerrin McEvoy and another of Chris Waller's runners, Smiling Manolito.

Cormac, the $1.75 favourite, won by a head.

Waller is among the leading trainers to support McDonald after the jockey's fall from grace for having an interest in a $1000 wager on Godolphin colt Astern, which enabled him to profit $4000.

The 26-year-old has ridden 30 Group One winners and is rated among the best of his profession in world racing.

He was a retained jockey for Godolphin before his disqualification but has resumed his career as a freelancer.

It was McDonald's first winner since Souchez at Flemington on November, 2016 and he was disqualified the following month.

"It's nice to get that one over and done with, even if I'd lost, just to get out there was good," he said.

"My legs are a bit jelly, I didn't need a tight finish to start off the day."