[3]: 554  The battle was preceded by a coup de chef of the reactionist forces, which was heated by the intrigue of the Spanish high command against Almonte and Márquez[4]: 79  and French pressure towards the replacement of Zuloaga.

However this plan was double-crossed by Ignacio Echegaray, from the fort San Carlos de Perote, who imprisoned his commander Francisco Paz and defected to the French Army with the garrison of 300 men and joined reactionist general José Gálvez.

General Zaragoza decided to change the orders given to Carbajal and direct him after the defectors, who on the 8th caught up with the deserted troops and after a two-hour fight at the Ixtapa valley dispelled them and took possession of the stolen equipment from fort Perote.

Lorencez stopped at Acultzingo on the 17th and sent General Edmond-Aimable L'Hériller of the 99th Infantry Regiment of the Line to Orizaba next morning with two pieces of artillery to make contact with the reactionists and guard the Rio Blanco-Puebla route at Ingenio.

[2]: 172 Márquez headed his troops for Rancho del Potrero on the 17th, from where he continued his trip alone to Tecamalaca to personally meet the French officers leaving his command to José Domingo Herran, who was about to join him the next day with the army.

This is what they did, and both sailed from Vera Cruz to Havana after the battle (Cobos then left for the United States with the intention of getting his exchange bills cashed in, but the agreement with the United States Minister to Mexico Thomas Corwin, by which the U.S. pledged to pay eleven million dollars to Juarez, was not ratified by the U.S. Senate, Cobos returned unpaid to Havana and ended up being shot in Matamoros).

[4]: 82 [5] While negotiating with the French high command on the day of 18th Márquez was informed that at the road crossing at Barranca Seca the Republicans and the reactionists were facing each other already in battle order and within firing range of each other.

The battle started slowly with none of the parties taking any risk and pushing back-and-forth within the firing range until finally at 5 p.m. the Republicans received major support from the main Eastern Army.

[7]: 136  Infantry Colonel José Mariano Rojo reached the battlefield with 1,100 fresh soldiers[6]: 475  and launched a mixed frontal assault breaking the center of Márquez[7]: 136  involving the "Hidalgo Battalion" and the Sappers Bataillon of San Luis.

They reunited with the reactionist left wing who also pursued the remnants of the Eastern Army and taking the place of the center only stopped at Venta of San Diego[7]: 137  when the night came.

[6]: 476  After one hour of fight hostilities were terminated at 6:15, the Mexicans were in full retreat,[2]: 172  along with the main Republican Army, with whom they retired to San Agustín del Palmar.