In 1973 Merckx rode in the Vuelta a EspaÃ a where he beat Luis Ocana and Bernard ThÃ venet and then went on to win the Giro d'Italia . Merckx 's final victory in the Giro d'Italia in the 1974 edition was a tight battle between Merckx and two Italians . Merckx won the Giro d'Italia in 1968 , 1970 , 1972 , 1973 and 1974 .