Several hours prior to when major combat began, Von Moltke had pleaded with Hafiz Pasha to withdraw to a more secure fortified position near Birecik and to await expected reinforcements, as Hafiz Pasha's forces were far outmatched in quality by the advancing Egyptians. Initially Hafiz acquiesced to Moltke, but not long after he decided to maintain his army's position, due to the advice of his mullahs.
The Ottoman troops under Hafiz Pasha were positioned at Mezar, southwest of Nezib, with the Nezib river on their left. Ibrahim advanced his force, under heavy Ottoman artillery fire, towards the Ottoman lines. At the same time, the Ottoman line began to take Egyptian artillery fire, and were suffering losses. By the time Ibrahim's infantry had encountered the Ottoman line, Hafiz's army was in complete rout, the Egyptian artillery having broken their morale.