On 9 September at Doncaster, Rock Sand attempted to complete the Triple Crown in the St Leger. Only four horses opposed him and he was sent off the 2/5 favourite. He reportedly had thing "all his own way" and won easily by four lengths from William Rufus, with Mead in third. Rock Sand's final start of the season came in the £10,000 Jockey Club Stakes over one and three quarter miles at Newmarket on 1 October. Ard Patrick had been retired by this time but Rock Sand was opposed by Sceptre. Rock Sand was beaten four lengths by the filly, who was conceding eighteen pounds– nine pounds more than weight-for-age– and won with "consummate ease".