Early years Varallo was born in Los Hornos, a district of
La Plata Partido in
Buenos Aires Province, on 5 February 1910. He made his debut aged 14, and early in his career gained the nickname
cañoncito (in English: "little cannon") for his shooting ability. In 1930, the forward was loaned for free by Gimnasia to
Vélez Sársfield to play for the team during their Pan-American tour. He totaled 17 goals during the tour.
Boca Juniors , c. 1935 Varallo moved to
Boca Juniors for the start of the
1931 season (the first professional season in Argentina) He continued to play for the club for the next nine years during which time he won the Primera División title three times, in 1931,
1934 and
1935, as well as coming runner up in
1933, when he was the
top goalscorer in the league and of South America scoring 34 goals. with 194 goals in 222 games (scoring average 0.87 per game), a record that stood until 2008 when it was broken by
Martín Palermo. During the 1930s Varallo formed strong partnerships with teammates
Roberto Cherro and
Delfín Benítez Cáceres, who both also scored over 100 goals for the club. In 1938, he was only able to play one game because of a bad knee injury and, although he played more frequently the next year, was forced to retire in 1940, aged 30. ==International career==