Her sire, Sir Ivor was an American-bred colt who was trained in Europe and won The Derby and the Washington D C International in 1968 before standing as a breeding stallion in Kentucky.
With the stable's first-choice jockey Lester Piggott opting to ride the Princess Elizabeth Stakes winner Lady Mere she was partnered by Tommy Murphy.
After being restrained in the early stages Lady Capulet moved up on the outside a quarter of a mile from the finish to dispute the lead with Bold Fantasy and Nanticious before accelerating away from her rivals.
She won by three lengths and a head from Bold Fantasy and Lay Mere with Nanticious (later to win the Ribblesdale Stakes) taking fourth place.
Piggott was again in the saddle later that month when Lady Capulet started odds-on favourite for the Pretty Polly Stakes over ten furlongs at the Curragh.