Complex sentence: Varallo was also an integral part of the Argentine team that won the 1937 South American Championship, scoring three goals at the tournament, including both goals in a 2--1 win over Chile.
Split into simpler sentences: Varallo was also a member of the Argentine team that won the South American Championship in 1937. He scored three goals during the tournament, including a brace in the 2--1 win over Chile.