Two days after the arrival of Giron in the valley of Pachacamac, a party of his army went out to skirmish with the enemy, on which occasion Diego de Selva and four others of considerable reputation deserted to the judges.  For several days afterwards his men continued to abandon him at every opportunity, twenty or thirty of them going over at a time to the royal army.  Afraid that the greater part of his army might follow this example, Hernandez Giron found it necessary to retreat from the low country and to return to Cuzco, which he did in such haste that his soldiers left all their heavy baggage that they might not be encumbered in their march.  On this alteration of affairs, the judges gave orders to Paulo de Meneses to pursue the rebels with six hundred select men; but the generals of the royal army would not allow of more than a hundred being detached on this service.  During his retreat, Giron, finding himself not pursued by the royalists with any energy, marched with deliberation, but so many of his men left him that by the time he reached the valley of Chincha his force was reduced to about 500 men.  Paulo de Meneses, having been reinforced, proposed to follow and harass the retreating rebels; but not having accurate intelligence, nor keeping sufficient guard, was surprised and defeated by Giron with some considerable loss, and obliged to retreat in great disorder.  Yet Giron was under the necessity to discontinue the pursuit, as many of his men deserted to the royalists.

Sensible of the detriment suffered by the royal interests in consequence of the disagreement between the present generals, Judge Santillan and Archbishop Loyasa, to which the defeat of Meneses was obviously owing, these very unfit persons for military command were displaced, and Paulo de Meneses was invested in the office of commander-in-chief, with Pedro de Puertocarrero as his lieutenant-general.  This new appointment occasioned great discontent in the army, that a person who had lost a battle, and rather merited ignominy and punishment for his misconduct, should be raised to the chief command.  The appointment was however persisted in, and it was resolved to pursue the enemy with 800 men without baggage.

Hernandez Giron, who retreated by way of the plain towards Arequipa, had reached the valley of Nasca, about sixty leagues to the southwards of Lima, before the confusion and disputes in the royal camp admitted of proper measures being taken for pursuit.  At this time, the judges gave permission to a sergeant in the royal army, who had formerly been in the conspiracy of Diego de Royas, to go into the enemys camp disguised as an Indian, under pretence of bringing them exact information of the state of affairs.  But this man went immediately to Hernandez, whom he informed of the quarrels among the officers and the discontents in the royal army.  He likewise informed him that the city of San Miguel de Piura had rebelled, and that one Pedro de Orosna was coming from the new kingdom