José Luís later fought in the Battle of Boquerón and the Battle of Potrero Sauce on 16 and 18 July 1866, respectively. He was transferred to the 1st cavalry division on 19 January 1867. He fought in the Battle of Tuyú Cué on 31 July, in the Battle of San Solano and in the Battle of Paré-Cué (part of the operations to encircle the Humaitá fortress) on 3 October. He was moved from the 1st cavalry division to the 3rd cavalry division on 12 October. He participated in the 28 Oct. 1867 Battle of Potrero Obella. He also fought in the Second Battle of Tuyutí on 3 November. After the fall of Humaitá in July 1868, José Luís took part in the Pikysyry maneuver that resulted in the "Dezembrada" (Deed of December), a series of decisive victories over the Paraguayans. At the head of the 2nd army corps after 6 December, José Luís fought in the Battle of Avay, in the Battle of Lomas Valentinas and in the Battle of Angostura.