Before the war
On the land battles, the United Provinces won all the main battles (Battle of Sarandí and Battle of Ituzaingó). Argentina was able to advance a lot through Cisplatina, not giving opportunity to the Empire of regaining terrain. But there were a lot of inconclusive battles and never invaded the capital.
On the sea battles the United Provinces and the Brazilian Empire won one of the two main battles, Argie won the Battle of Juncal, while Brazil won the Battle of Monte Santiago. And most of the rest of the battles were inconclusive. Despite the close fights the argentine navy was small and ended up in a bad state after the war.
Fun fact: during the Battle of Ituzaingó Argentina theft a marching song about the battle that Brazil was making in case of winning the fight. Argentina won and made the march one of its presidential emblems and mocks Brazil even to this day by playing the march.