Alfaro started his professional career with
Newell's Old Boys in the mid-1970s. In 1981, he was signed by
Panathinaikos in
Greece, and he played under the Greek surname Bistakis. He returned to South America later that year to play for
América de Cali in
Colombia where he won two league championships. In 1983, he returned to Argentina to play for
River Plate, he was part of the championship winning team of 1895-1986 and helped the team to win their first ever
Copa Libertadores in 1986. The club also won the less prestigious
Copa Interamericana during his time at the club. He was selected to play for
Argentina in the
Copa América 1987. In 1987, he returned to Newell's Old Boys where he won another league title in 1987–1988. Towards the end of his playing career he had a spell in
Chile playing for
O'Higgins until his retirement in 1992. ==Managerial career==