Nicknamed "El Chino" (the Chinese), Guasch started his career at the small regional club Guaraní de Davaru in the city of Carapeguá, in 1975. Scouts from Club Olimpia noticed his talent and one year later, in 1976, he was playing in the Paraguayan first division. Guasch became Olimpia's captain in 1988 and he remained with the club until his retirement in 1991, winning several national and international championships. He is regarded as one of the club's most important players.
