Three Chilean columns of almost 3,900 soldiers attacked a numerically inferior Peruvian contingent of 3,046 troops at Tarapacá - 500 of which were at Quillahuasa, 1 hour away from the battlefield - commanded by Gen Juan Buendía, resulting in a harsh defeat.

Following a significant defeat at Dolores well inflicted by an outnumbered Chilean contingent - which cost the Allies all their artillery - the remnants of the Peruvian army were scattered all across the desert, demoralized and almost leaderless.

[4] Later, Arteaga was informed that the Peruvian numbers were greater than expected, so he sent another column made up of the 2nd Line and Artillería de Marina regiments, the Chacabuco Battalion, 30 more Cazadores a Caballo riders and another artillery battery.

In receipt of this news, Vergara asked Arteaga for instructions, his request creating great anxiety among Chilean High Command and troops.

Arteaga did not properly prepare the Chilean forces dispatched for battle, meaning they carried insufficient amounts of food, water and ammunition,[5] all of which had serious consequences later on.

Worse, since they were now 70 km (45 mi), across desert terrain, from the nearest source of Chilean supplies at Dolores, Arteaga realised that their only salvation was to attack.

6 km (3.7 mi) north east of Tarapaca, within the stream bed and astride any route of retreat from the town, lay the village of Quillaquasa.

With the advantage of hindsight, there is a strong case to argue that the Chilean attack was poorly planned, since, despite being heavily outnumbered, Arteaga divided his force into three columns, thereby weakening even more any chance of victory.

Given the dispersal of the Peruvian forces at the previous battle, encircling the enemy and then denying them an escape route promised the chance of a decisive outcome should the Chileans prevail.

Buendía was well aware of the Chilean presence, notified by Andrés Avelino Cáceres and Francisco Bolognesi that one column was advancing over the plateau and another one was moving towards Tarapacá’s den.

At 03:30 Santa Cruz departed from Isluga while a dense fog covered the surroundings, and an hour later Ramírez and Arteaga began their movement.

At 10:00, the fog vanished and Cáceres division could easily climb Visagra hill and attack Santa Cruz’ column from his rearguard, isolating him from Ramírez and Arteaga.

[8] Cáceres division was formed by the Zepita and 2 de Mayo regiments, and later strengthened by the Ayacucho and Provisional Nº 1 of Lima battalions of Colonel Bedoya.

Ramirez’ progressed without inconvenience passing through Huaraciña and San Lorenzo along the river, but upon reaching a small mount at Tarapacá’s entrance, was received by enemy fire.

The Chileans came back for their surprise and charged into the town only to be shot at point blank range from every house and building, suffering heavy damage.

Dávila’s men appeared suddenly over Huariciña; Herrera’s and Bolognesi’s divisions attacked the troops at the river, and at the eastern and western heights, surprising the Chileans again.

The second in command of the Artillería de Marina Regiment formed 50 shooters along with two cannons and held the attack for an hour, until Arteaga realized the battle was lost and ordered the retreat.

The Allies left Tarapacá, withdrawing north-west to Arica on the coast, moving through the area close to the mountains to avoid the Chilean cavalry attack.