Because of disagreements with Simón Bolívar, Lavalle returned to Buenos Aires by the end of 1823. He would later govern Mendoza Province for a short time. He then fought in the war against Brazil in command of 1,200 cavalry, with great episodes of valour in the battles of Bacacay and Ituzaingó in February 1827, beating the forces of General Abreu and being himself proclaimed General on the field of battle itself.