On 20 December 1945, Brazil got their biggest win over Argentina, beating them 6-2 in the Roca Cup.
The Roca Cup was a contest between the two national teams played at irregular intervals from 1914 and 1976. There were four previous tournaments, of which Argentina won the last three. The most recent one consisted of three games in 1940, with Argentina winning two of them by margins of 6-1 and 1-5.
The 1945 tournament, hosted by Brazil, also included three games, played between 16 December and 23 December. Brazil won the first match 3-1 in São Paulo, then moved to Rio de Janeiro for the second one.
There, Argentina took the lead with a 31st-minute goal from Adolfo Pedernera, but Brazil got strikes from Ademir Menezes (pictured) (34') and Leonidas da Silva (39') to lead 2-1 at the break. Argentina drew level in the 46th minute through Rinaldo Martino, but then the floodgates opened for Brazil with goals from Zizinho (64'), Chico (75'), Heleno de Freitas (82'), and another from Ademir (84'). The 6-2 scoreline remains Brazil's biggest margin of victory over Argentina (though Argentina's 6-1 win in 1940 remains the largest win in the rivalry).
Brazil went on to win the third game 3-1 and claimed the Roca Cup for the first time since 1922.