During the night of May 8, following disappointments at the Battle of Palo Alto, Arista chose to withdraw to the far more defensible position of Resaca de La Palma, a dry riverbed (Resaca is the Spanish term for a Wadi[?]), and establish himself while waiting for Taylor's next move.
On the morning of May 9th, Taylor's seventeen hundred troops engaged a Mexican force by now swollen to four thousand with Arista's reinforcements. Arista's carefully laid plans for engaging the Americans at Resaca were, however, somewhat diluted due to political infighting in the Mexican officer corps and difficulty communicating in the rough terrain of the battlefield.
Resistance on the part of the Mexicans was stiff, and the American forces nearly suffered a reverse before, in a stroke of amazing good fortune, a force of U.S. Dragoons managed to suprise the flank of the Mexican lines and force a retreat. Two counter-attacks on the American position were defeated and the Mexican Army fled the field, leaving behind a number of artillery pieces, Arista's silver service, and the colors of Mexico's lauded Tampico Battalion.
The resulting embarassment at a near victory turned into a defeat caused the removal of Arista as commander of Mexico's Army of the North and a serious reassessment of Mexican strategy. Unfortunately for the Mexicans, corruption at the very highest levels of Mexican government failed to produce a cohesive strategy for much of the fighting, despite increased skill and success on the part of the Mexican Army.
Bauer, K. Jack The Mexican War, 1846-1848