In June Cossack ran twice at Royal Ascot. In the Gold Vase he was involved in a close finish, dead-heating with the filly Canezou for second place, a head behind the winner Glenalvon, after looking the likely winner. A day later, Cossack ran in the Emperor of Russia's Plate, in front of a large crowd which included the Queen and Prince Albert. He finished third, beaten two lengths, behind Van Tromp and Chanticleer, in a race which, according to Bell's Life, created an "extraordinary degree of excitement".
