Sir Ivor returned in late September when he ran in the Prix Henry Delamarre at Longchamp in which he finished half a length second to Prince Sao, to whom he was conceding nine pounds. One week later, he returned to Longchamp for the Prix de l'Arc de Triomphe. Sir Ivor, whose best distance was probably 10 furlongs was outstayed by the favourite, Vaguely Noble, who won by three lengths. Sir Ivor finished four lengths ahead of the remainder of the field to take second. Two weeks after his run in Paris, Sir Ivor appeared at Newmarket, where he won the Champion Stakes easily by two and a half lengths from a field which included Taj Dewan. On his final start, Sir Ivor was sent to the United States for the Washington, D.C. International at Laurel Park, Maryland. Piggott held the colt up before producing a "furious stretch drive" to lead in the last twenty yards and beat Czar Alexander, with the American Champion Male Turf Horse Fort Marcy in third.