Americans and Carrizo Indians dismounted, hitched their horses and fell in a ravine, known as the Alto Limpia, and, taking cover behind the mesquite bushes immediately to their left, quietly crept along until they had taken up position behind a number of large rocks in that part of the arroyo nearest the enemy. The Mexican Federalists did not come up. They paraded some distance off, out of reach of the enemy cannon. Zapata did all he could to lead them up, but they refused obedience. Pavón, perceiving that he was not to be attacked by the main force of the enemy, turned upon the Americans, who he thought had halted behind the timber to await the coming up of the main body. The Centralist infantry, supported by cavalry, extended itself down the hill to a line of straggling trees which bordered the arroyo and thus unwittingly took a position within eighty yards of the Texan rifles. The Texans permitted the Centralist infantry to form, and the first intelligence that Pavón's men had of the proximity of their neighbors was from a well directed fire which they withstood for five or ten minutes, before they retreated precipitantly under cover of their artillery.

Thinking to use his artillery to advantage to annihilate the enemy in the ravine, Pavón now directed his four pieces of artillery upon the Texan position and kept up a cannonade for four hours, until satisfied by the silence of the Americans that he had slain them all (actually, they had been resting and some of them even sleeping). Convinced that the Texans surely must have been slaughtered by now, Pavón moved with his whole force against their position; but when the Centralists arrived within easy gunshot of the ravine, at a point about as near as their infantry had reached at the first onset, Cameron rose up and fired upon the drummer, who fell dead.[104]  This was the signal for a general fight, the first real opportunity afforded the Texans to use their rifles effectively. The whole company now arose to pour a destructive fire upon Pavón and to charge his entire line. By this time, the main Federalist force came up and charged the enemy's right flank "without making an impression, though they suffered severely for their temerity."[105]  Falling back they formed behind their Anglo-American friends. The Centralists withstood the fire of their opponents for five