 The rivalry developed in the 1980s from numerous controversial encounters between the two clubs in that decade's Brasileirão and Copa Libertadores editions.It remained through the following years, and is considered the biggest interstate rivalry in Brazilian football.The first encounter between the two teams happened on 16 June 1929, a friendly in Atlético's home ground, the Presidente Antônio Carlos stadium, which Flamengo won 3–2.