, younger brother and commander of
José Miguel Carrera's army at Las Tres Acequias On the morning of 26 August, the then
brigadier O'Higgins crossed the Maipo River and on to the level ground on the other side. His intention was to advance rapidly on
Santiago and thereby to defeat Carrera; because of this, he did not initially realise the size and disposition of Carrera's forces. At 13:00 hours, O' Higgins' advance parties, under the command of
Ramon Freire, joined combat with the forward echelons of Carrera's forces, under the command of José's youngest brother, Colonel
Luis Carrera, protected by a low bank. Luis Carrera had deployed his forces with the infantry to his right, the artillery to the centre, his cavalry to his left and behind these, a line of eight hundred cavalry militia from
Aconcagua under the command of the colonel
José Maria Portus. These militia were badly equipped, of poor quality, and were only deployed during the final phases of the battle. Eschewing further reconnaissance, O'Higgins ordered his men forward in a determined attack against the larger enemy force, apparently optimistic following the early preliminary victory delivered by
Freire along the bank. After an unfruitful cannonade, O' Higgins attacked in force at 16:00, placing his infantry in the centre of his line, supported by four guns, and dividing his cavalry between both flanks. After one hour of fruitless attack, and having received numerous losses without causing much damage to the defenders, O'Higgins' forces began to retreat in relative disorder. This moment was seized by the cavalry of Luis Carrera, who ordered
Diego Jose Benavente to encircle the enemy's right flank and begin to further disrupt his line. This was followed by the mounted militia of Aconcagua charging the middle of O'Higgins' line, breaking through it and taking numerous prisoners, amongst them four senior officers. O'Higgins' men fled, mainly to the south, attempting to cross the Maipo river and seeking safety in the buildings around
Chena. O'Higgins' own mount had collapsed wounded, and he retreated from the field on a borrowed horse, leading a unit of 100 men to safety. Meanwhile, the bulk of the 3rd division of Carrera's force, under the command of José Miguel Carrera himself, had been positioned on the suburbs of Santiago at the beginning the battle. Despite a force march, it did not arrive in time to take part in the main action. When the cavalry from the 3rd division arrived, it joined the units chasing O'Higgins' men from the battlefield – but as the sun set around 18:30, Carrera's men gave up the pursuit. ==Consequences of the battle==