After winning eighty races as an amateur racer, he turned professional on 29 April 1965 when he signed with . His first major victory came in the Milan–San Remo a year later, after switching to . After the 1967 season, Merckx moved to , and won the Giro d'Italia, his first Grand Tour victory. Four times between 1970 and 1974, Merckx completed a Grand Tour double. His final double also coincided with winning the men's road race at the UCI Road World Championships to make him the first rider to accomplish cycling's Triple Crown. Merckx broke the hour record in October 1972, extending the record by almost 800 meters.