Brazil x Argentina

Origins
I think that Brazil x Argentina is one of the biggest rivalries in the whole world. The beginning of this derby of soccer can be attributed to before football became so popular in both countries. Formerly, when Brazil and Argentina were Portugal and Spain colonization, they fought a lot. So, this rivalry is till now a days existing. Their rivalry is found in almost all sports but in soccer, that is something special. Neither the Brazilian team nor the Argentinean team wants to loose. Today Brazilian and Argentinean always keep competing.

Messi (left) and Rafinha (right)

Source picture: Wikipedia