Viejo won the 11th stage of the 1976 Tour de France with a time difference of 22 minutes and 50 seconds to the second-placed cyclist; this is the largest lead in the Tour de France after the Second World War. He also won the Tour de Pologne 1972.
Viejo's impressive performance led to him winning the 11th stage of the 1976 Tour de France by a considerable margin of 22 minutes and 50 seconds over his nearest competitor; this remains the largest lead in the Tour de France since World War II. He also had notable success at the Tour de Pologne in 1972.