General Scott had planned to open up the way for the march of his army to the City of Mexico by the way of Padierna.  Knowing or believing that a stubborn defense would be made by the Mexicans, he had ordered General Worth to march from San Antonio on the morning of August 20th, with Garland’s brigade, by way of San Augustin to Padierna, to be followed by General Quitman, who was ordered to leave a cavalry force to hold San Antonio.  But General Persifor F. Smith had won the battle before these troops arrived.

A sufficient guard having been left with the prisoners, General Persifor F. Smith was ordered with his brigade, the Mounted Rifles and Engineers, in pursuit of the fleeing enemy.  They were attacked at San Angel, but the attacking party were soon driven off.  General Pillow joined these forces at San Angel, and General Scott came up with them at Coyoacan, where he had ordered the army to halt.

From this point in the direction of the capital, Churubusco was one mile; two miles to the southeast was San Antonio.  Churubusco is about six miles south of the City of Mexico, on a river of the same name, and on the road from San Angel and San Antonio from San Augustin.  General Scott on his arrival ordered Captain Lee, with Captain Phil Kearney’s company of the First Dragoons and a company of the Mounted Rifles, to make a reconnoissance.  In the meantime Pillow and Cadwallader were to attack San Antonio in the rear, General Worth assailing it in front.  A reconnoissance having been made of the convent of San Pablo, in the town of Churubusco, a brigade from Twiggs’s division, a part of Smith’s brigade, Riley’s brigade, and Taylor’s battery were ordered to attack.  After the defeat of General Valencia at Contreras, General Worth returned with Garland’s brigade in front of San Antonio.  His orders were to attack as soon as Pillow and Twiggs, moving from Contreras, approached in the rear.  Worth ordered Clarke’s brigade to move over the pedregal and turn the right flank of the fortifications at San Antonio and cut the enemy’s line of communication.  Henry Francis Clarke’s brigade was attacked on its march, but dispersed the attacking force, and soon encountered the rear of the Mexicans from San Antonio and engaged them.  Pillow with Cadwallader’s brigade, joined Worth in pursuit of the fleeing Mexican troops and both attacked the tete-de-pont in their front.  Riley’s brigade having been ordered forward, General Scott ordered Pierce’s brigade to move by the road leading north from Coyoacan across the Churubusco River by a bridge, turn to the right, and seize the causeway in the rear of the tete-de-pont.  General Scott, learning that General Shields, in the rear of the Mexican lines, was in danger of being cut off and captured, ordered Major E.V.  Sumner with the Mounted Rifles under Major W.W.  Loring, and the Second Dragoons under Captain Henry Hastings Sibley, to his support.  The attack of the Americans being persistently pressed on all sides, the Mexicans gave way and made a precipitous retreat, pursued by the victorious Americans.