Revolving Door has completed a double for trainer Clinton McDonald, with a strong on-pace first-up win at Moonee Valley.

Having his first start since being gelded, Revolving Door took out the Epworth Medical Imaging Handicap (1200m) on Saturday.

Ridden by Mark Zahra, Revolving Door ($6.50) scored a half-length win from Liberty Song ($10), with the $4.40 favourite Highland Beat the same margin away in third.

McDonald said the gelding operation following one start in the autumn had helped switch on the three-year-old.

Revolving Door ran second to Sacred Elixir in the Group Three Guineas Prelude last spring and McDonald kept him a colt in the hope of developing him into a stallion prospect.

But Revolving Door had other ideas when resuming in Adelaide in March.

"He's always been a nice horse and being gelded has helped switch him on," McDonald said.

"He's a racehorse now and he's not worrying about other things."

McDonald said the Listed AR Creswick Stakes (1200m) at Flemington on July 8 was the next race on Revolving Door's agenda, after which he will consider spring options.

The trainer was concerned by the wide draw but was happy to see the gelding jump well and press forward.

"Mark made the decision to go forward and that's why you put these good jockeys on because they make the right decisions," he said.

Zahra said that after beginning well he elected to follow Chelsea Hall across on Liberty Song.

It was Liberty Song's third successive placing in the metropolitan area, all under half a length.