Two runners at the meeting is all it has taken for the Trent Busuttin and Natalie Young stable to claim a winning double at Caulfield.

After Shenandoah got home narrowly in the opening race on Sunday's card for stable apprentice Zac Spain, senior jockey Stephen Baster kept a perfect record on lightly raced three-year-old Keen who claimed a narrow win in the Sandra Cheevers Handicap (1400m).

Keen won a maiden by 4-3/4 lengths at Cranbourne last month on debut but had to work overtime to keep an unbeaten start to his career on Sunday in the benchmark-64 handicap.

Baster angled out on Keen at the top of the straight and the colt hit the front and withstood a strong challenge from Mahamedeis.

The pair went head to head over the final 100m with $3.20 favourite Keen getting home by a nose, with a further 1-3/4 lengths to Eclair Calling third.

Baster believes there's improvement to come from Keen as he matures.

"There's not a lot of him if you see him without a saddle on and he's still green," Baster said.

"The other horse probably made him fight, because he kind of got to the front and stargazed a bit until the other horse came at him.

"So he's still new and there's plenty of improvement there I think.

"I think next preparation he'll be a lot better horse."