Apprentice Zac Spain has maintained a perfect record on Masculino after partnering the three-year-old gelding to a convincing win at Caulfield.

Spain rode the Mick Price-trained Masculino for the first time at Flemington on June 9 for a win over 2000m and retained the ride for Saturday's Keno Heads Or Tails Handicap over the same distance.

The apprentice allowed Masculino to stride forward after about 400m of Saturday's race to sit just off leader Under Oath in second before the $2.60 favourite took over early in the straight.

Masculino strode clear over the final 200m to beat Under Oath ($8.50) by three lengths with another 2-1/4-lengths to Jeddah Aheadah ($18) third.

Spain has only recently transferred to the Price stable on loan and was delighted to partner Masculino to another victory.

"It was his second time over the 2000 metres and he was fit and ready to go today," Spain said.

"He put the field away really good and is racing in terrific form."

Price's stable representative Mick Nolan praised Spain for his ride.

"He has only come to us a couple of weeks ago but he's a hard worker and he's got a hell of a future ahead of him, I reckon," Nolan said of Spain.