A horse whose nervous disposition made him a no-hoper on far-flung country tracks pulled himself together well enough to win at Moonee Valley on Saturday.

Stable Star had finished seventh of nine at Mildura three runs back and had struggled home near the back of the field at Casterton before that.

But the advice of one jockey led to another scoring a breakthrough city win on the gelding in the DPOS Displays Handicap (2500m).

"He's always shown us something, but he's taken a while to learn," said trainer Terry O'Sullivan.

"When you hang onto him in his races he goes into panic mode and holds his breath which isn't much good to him."

Michelle Payne found the key to Stable Star when she rode him at Mildura, telling O'Sullivan the run was a lot better than it seemed, suggesting the horse be allowed to stride freely in his races.

Fellow rider Nikita McLean took Payne's advice at Stable Star's previous start when he finished a close second at Caulfield and again when he went one better at the Valley.

McLean had Stable Star ($21) in front from soon after the start and he relaxed well enough to come again after being headed and score by a long neck from Angelology ($8) with Arch Fire ($6) a half-length back in third.

The term "champion" got thrown around as carelessly as ever at Moonee Valley, but Leon Corstens' exaggerated opinion of his winner Alpha Proxima was almost forgiveable.

A couple of years ago Corstens trained Alpha Proxima to win a 955m race at the Valley and on Saturday he coaxed a 1600m victory from him.

"He's a champion this horse," Corstens said.

"He tries every time, he gives everything, you can't ask for more."

Alpha Proxima ($10) was among the leaders all the way, taking control of the Boscastle Handicap at the 500m and then scoring an untroubled 2-3/4 length win from Lucky I'm Barefoot ($8) with a short neck to Spacecraft ($6.50) in third place.

Corstens had further opportunity to praise one of his team when star filly Commanding Jewel turned in an impressive between-races gallop.

Commanding Jewel could return to racing in two weeks at Caulfield, commencing a campaign that Corstens is hoping will end back at Moonee Valley in the Cox Plate.