The Highclere Thoroughbreds-owned filly came from behind under Jack Mitchell to score decisively in a fast time.
The leaders went hard in front and Jack was content to settle Stocking on the rail towards the rear of the field.
She travelled smoothly and eased into contention through the pack as the pacesetters begun to show the effects of the strong early pace.
Stocking showed a decent turn of foot to strike the front inside the final furlong before coasting home to win by a length and three quarters.
Roger said: "Stocking has been hitting the crossbar since she last won here in June so she deserved to win again. They have gone hard today and she has really done it nicely."