Curuzu was taken by surprise by the baron of Porto Alegre, but Curupaity resisted the 20,000 Argentines and Brazilians, led by Mitre and Porto Alegre, with support of the squadron of admiral Tamandaré.
Curuzu blev overrasket af baronen af Porto Alegre, men Curupaity stod imod de 20.000 brasilianske og argentinske styrker under ledelse af Mitre og Porto Alegre, med hjælp fra eskadren under admiral Tamandaré.