The defeat of Canterac's expeditionary forced La Serna to bring Jerónimo Valdés from Potosí, who came on a forced march with his troops. The royalist generals debated their plans. In spite of the signs of support from within the besieged Cusco, the viceroy rejected a direct assault because of his army's lack of training, having been enlarged by the massive return of peasants a few weeks earlier. On the contrary, he intended to cut Sucre's rearguard through march and countermarch maneuvers, which is what led to the encounter in Ayacucho, along the Andean range. Thereby, the royalists planned a quick strike which they made on 3 December in the Battle of Corpahuaico or Matará, where they caused the liberator army more than 500 casualties and the loss of a large part of its ammunition and artillery, to their own losses of only 30 men. However, Sucre and his adjutant managed to keep the troops organized and prevented the viceroy from exploiting this local success. Although having suffered important losses of men and materiel, Sucre preserved the United Army in an ordered retreat, and always situated it in secure positions of difficult access, like Quinoa field.