Meanwhile, about an hour earlier, Worth, by a skilful and daring movement upon the enemy's front and right at the hacienda of San Antonio, had turned and forced that formidable point whose garrison no doubt was panic struck by the victory of Contreras. The enterprise was nobly achieved. Colonel Clarke's brigade, conducted by the engineers Mason and Hardcastle, found a practicable path through the Pedregal west of the road, and, by a wide sweep, came out upon the main causeway to the capital. At this point the three thousand men of the Mexican garrison at San Antonio, were met in retreat, and cut by Clarke in their very centre;—one portion being driven off towards Dolores on the right, and the other upon Churubusco in the direct line of the active operations of the Americans. Whilst this brave feat of out-flanking was performed, Colonel Garland, Major Galt, Colonel Belton, and Lieutenant Colonel Duncan advanced to the front attack of San Antonio, and rushing rapidly on the flying enemy, took one General prisoner, and seized a large quantity of public property, ammunition and the five deserted guns.
Thus fell the two main keys of the valley, and thus did all the divisions of the American army at length reach the open and comparatively unobstructed plains of the valley.
Worth soon reunited his division on the main straight road to the capital, and was joined by General Pillow, who, advancing from Coyoacan to attack the rear of San Antonio, as we have already related, soon perceived that the hacienda had fallen, and immediately turned to the left, through a broken country of swamps and ditches, in order to share in the attack on Churubusco. And here, it was felt on all sides, that the last stand must be made by Mexico in front of her capital.