Ragusa was a small and weak foal who needed to be hand fed on milk and eggs, and Guggenheim decided to sell him.
On his first appearance of the 1963 season, Ragusa was sent to England, where he started favourite for the Dee Stakes at Chester Racecourse but finished second to My Myosotis.
In June, he started a 25/1 outsider for the Derby at Epsom and exceeded expectations by finishing third of the twenty-six runners behind Relko and Merchant Venturer.
At the Curragh later that month, Ragusa won the Irish Derby by two and a half lengths after Relko was withdrawn at the start.
In July, Ragusa started at odds of 4/1 in a field of ten runners for Britain's most prestigious all-aged race, he King George VI and Queen Elizabeth Stakes at Ascot.