It has been a spring of discontent for the Anthony Cummings stable and few horses have been as frustrating as Spy Decoder.

Fast-tracked to Group One company in the Epsom Handicap, the four-year-old got back from a wide gate and used most of his energy fighting his rider.

On Wednesday, Spy Decoder found himself banished to midweek grade and while his racing manners still fell short, his class did not.

After some initial disagreement with jockey James McDonald, Spy Decoder relented and angled off the fence half-way up the Kensington straight to power over his rivals and win the Inglis Plate by two lengths.

For Cummings's son and foreman Edward, the victory was a relief.

"He's obviously still a bit gawky, he went to go right when James wanted to go left but he got there in the end and put them away like he ought to have," he said.

"He's always shown the ability, he's always just had a baby brain for racing.

"We're starting to learn exactly what it takes to get him right for race day. It has been a difficult process but it'll be worth the wait."

Cummings started the spring with a handy team but it was depleted when several horses, including the progressive As Needed and one-time Thousand Guineas hopeful High Above, went by the wayside.

Hopes were high for Spy Decoder but the bar has been lowered, for now.

Edward Cummings confirmed the horse would head to Melbourne for a "benchmark race or thereabouts" with the primary aim of ironing out his kinks and boosting his bank balance for the autumn.

"If we can do that now and get that sorted when he comes back in the autumn we don't have to worry about all that," Cummings said.

"The target for today was to win. The horse needs to learn to win because he's got a stack of ability."

Another of Wednesday's winners heading south is Godolphin mare Entertains.

The second leg of a race-to-race double for McDonald, trainer John O'Shea confirmed Entertains would run in a 1700-metre support race on Melbourne Cup day.