When Carvajal was come within about two leagues of that place, Centeno retired a short space to the other side of the city, taking post on the side of a river in what appeared to him strong ground, and Carvajal took possession of the tambo of Paria, about a league from the camp of Centeno.  Next day, Centeno sent fifteen well mounted musqueteers to bid defiance to Carvajal, and to challenge him to battle.  On arriving within a stones throw of the tambo, they required a conference with Carvajal, to whom they delivered the following message:  “That Centeno was ready to give battle in the cause of his majesty; but if Carvajal, who had grown old in the royal service, would return to his duty and abandon the service of the usurper, Centeno and all his followers would be happy to serve under his command.”  To this message Carvajal only returned abusive language, and the two parties mutually reproached each other as rebels and traitors.  After some time spent in this manner, the fifteen royalists discharged their musquets and returned to Centeno, to whom they gave an account of the number and disposition of the enemy.  This occurrence took place on Holy Friday in the year 1546.

Immediately after this defiance, Carvajal put his troops in motion to attack the royalists, but Centeno thought proper to retire to a more advantageous post, not deeming it prudent to run the risk of a pitched battle, and meaning rather to harass the enemy by means of skirmishes and night attacks.  He was likewise in hopes that a good many of those who followed Carvajal might come over to his side as opportunity offered, as he understood many of them were much discontented with the harsh and brutal behaviour of the lieutenant-general, whom they served from fear and constraint, not from attachment.  Besides, Centeno was unwilling to run the risk of battle, as Carvajal though inferior in cavalry to the royalist party was greatly superior in point of fire arms.  In fact this resolution of retreating was much against the inclination of Centeno, who wished to have given battle to Carvajal; but as all the inhabitants of La Plata on his side opposed that measure, he was obliged to conform to their wishes, yet always determined to give battle on the first favourable opportunity.  Centeno accordingly retreated fifteen leagues that day, and was followed by Carvajal with great diligence, insomuch that the hostile parties encamped at night very near each other, on which occasion Carvajal confided the guard of his camp to such of his followers as he could most surely depend upon.  Towards midnight, Centeno detached eighty horsemen to assault the camp of the insurgents, which they did accordingly with much spirit, making several discharges of their fire arms, but without any favourable impression; as Carvajal drew up his troops in order of battle, and kept them all night in their ranks, strictly forbidding any one to quit their post on any pretence, lest some might desert over to the enemy.  At break of day, Centeno decamped