This battle was fought in the Valley of La Berrueza, in the district of Estella, on the 29th of December 1833 and can be considered the first Carlist combat since these forces had previously limited themselves to running away. Zumalacárregui had just taken command and decided to organise the Carlist army. The Alava and Navarre battalions were merged and although the forces were running low on ammunition, Zumalacárregui believed that the time had come to train his troops.
Zumalacárregui had around 3,000 men at his command, whom he stationed in the middle of the Valley of Berrueza, near Asarta. When the Liberals attacked, they had many more men fighting under the orders of Generals Lorenzo and Oraa. The Carlists stood their ground but soon ran out of ammunition. Oraa led the decisive, left-flank attack in the direction of Nazar. Although Zumalacárregui ordered a retreat, he was satisfied with the conduct of his troops. While the Carlists ended the battle with 50 casualties, the Liberals themselves lost over 300 men.
The Carlists retreated to Campezo after taking refuge in, Améscoa. The Liberals could not prevent the escape of the Carlists and returned to Pamplona to re-assemble. The importance of this battle lies in the fact that the Carlists proved that they could hold off a Liberal attack. It was here that the Carlists earned the respect of the Liberal generals, proving that they could confront them with something beyond mere guerrilla warfare.