The "Blood in the Water" match (Hungarian: melbourne-i vérfürdő lit. Blood bath of Melbourne; Russian: Кровь в бассейне, translit. Krov' v basseyne, lit. 'Blood in the swimming pool') was a water polo match between Hungary and the USSR at the 1956 Melbourne Olympics. The match took place on 6 December 1956 against the background of the 1956 Hungarian Revolution, and saw Hungary defeat the USSR 4–0. The name was coined after Hungarian player Ervin Zádor emerged during the last two minutes with blood pouring from above his eye after being punched by Soviet player Valentin Prokopov.
Tensions were already high between the Hungarian and Soviet water polo teams, as the Soviets had taken advantage of their political control of Hungary to study and copy the training methods and tactics of the Olympic champion Hungarians.
Then, on October 23, 1956, a demonstration by students of the Budapest University of Technology and Economics escalated into an uprising against the Soviet puppet government in Budapest. On November 1, Soviet tanks began rolling into Hungary and from November 4 to November 10 forces began suppressing the uprising with air strikes, artillery bombardments, and tank-infantry actions.
At the time, the Hungarian water polo team was in a mountain training camp above Budapest. They were able to hear the gunfire and see smoke rising. The players were the defending Olympic champions; with the Summer Olympics in Melbourne two months away, they were moved into Czechoslovakia to avoid being caught in the revolution. The players only learned of the true extent of the uprising and the subsequent crackdown after arriving in Australia and they were all anxious for news of friends and family.