The win was the seventh time Stewart had been in the winner’s stall since turning his hand to training just over 12 months ago.
The four-year-old Masterplan, owned by his Stewart’s mother Pauline, gave the former jockey his maiden win as a trainer at Stanthorpe in October last year.
Masterplan has been in the winner’s stall on five other occasions for Stewart at Kilcoy (twice), Warwick, Burrandowan and Esk.
Stewart rode more than 1,460 winners during his career as a jockey but is on the sidelines recovering from a serious pelvis injury which has required multiple surgeries.
The $105,000 Country Stampede Final will be run at Doomben on November 30 along with the $200,000 Country Cups Challenge Final.