Masahiko Kimura vs. Hélio Gracie

The fight between Japanese judoka Masahiko Kimura and Brazilian jiu-jitsu founder Hélio Gracie was held at the Maracanã Stadium in Rio de Janeiro, Brazil on October 23, 1951. It was held as a special challenge, with no titles on the line: Gracie was the self-proclaimed national jiu-jitsu champion, seen as a regular judo 6th dan by Kimura, while Kimura, dubbed the world's jiu-jitsu champion by the Brazilian press, was coming from a career in professional wrestling and teaching of judo.

Source: Wikipedia — Masahiko Kimura vs. Hélio Gracie (CC BY-SA 4.0)