They started the battle supporting Mexican infantry by firing on U.S. lines as the Mexicans advanced on them, then later decimating an artillery battery directly opposite them on the battlefield (Washington's 4th Artillery, D Battery). A small number of were dispatched with a division commanded by Manuel Lombardini with the express purpose of capturing the 4th's cannons once the crews had been dealt with. As the division got close enough they charged the artillery battery, bayoneting whoever remained and routing the rest, leaving the attached free to haul away two six-pound cannons. These cannons would later be used by Mexican forces at the Battle of Contreras.