Suleyman Askeri chose to attack the British positions at Shaiba, southwest of Basra, rather than assault the city directly. At 5 AM on April 12, Ottoman guns opened a bombardment against the British camp. As evening fell, Ottoman infantry crawled forward through the darkness, probing for gaps in the barbed wire. They were repulsed. By morning on the 13th, the attackers had withdrawn to prepared positions at Barjisiyeh Wood, a stand of trees that provided the only cover in the flat, waterlogged terrain. The pause was brief. Ottoman scouts and Arab irregulars began attempting to slip around Shaiba entirely, aiming to bypass the garrison and reach Basra from another direction. General Charles Melliss, commanding the British defense, recognized the flanking threat and moved to counter it.

Melliss first sent the 7th Hariana Lancers and then the 104th Wellesley's Rifles to intercept the Arab irregulars trying to outflank Shaiba. Both attacks failed. The irregulars were too dispersed, the terrain too waterlogged for mounted troops, and the initial attempts to dislodge them fell apart. Melliss adjusted. He committed the 2nd Dorsets and the 24th Punjabis, supported by concentrated artillery fire. This time the attack broke through. Four hundred Arab irregulars were captured and the rest scattered into the flooded countryside. They would play no further part in the battle. Their departure stripped Suleyman Askeri of three-quarters of his force and left his Ottoman regulars to face the British alone. It was a loss the Ottoman commander would never forgive -- and one for which he would later take his own life.

On the morning of April 14, the British left Shaiba and went looking for the remaining Ottoman force. They found it at Barjisiyeh Wood. Fighting began around 10:30 AM and lasted until 5 PM -- six and a half hours of grinding infantry combat. Melliss had to reposition his forces under fire to bring them to bear on the Ottoman positions, a dangerous maneuver that exposed his troops in the open. The Ottoman regulars fought hard. Their fire was intense, and by 4 PM the British attack had stalled. Men were thirsty, ammunition was running low, and the Ottoman infantry showed no sign of giving up. Then the 2nd Dorsets fixed bayonets and charged. The sight of the Dorsets surging forward pulled the Indian troops into the attack behind them. The combined bayonet charge overwhelmed the Ottoman lines. The regulars broke and retreated from the field. The exhausted British, lacking transportation and with their cavalry committed elsewhere, could not pursue.

The consequences of Shaiba reached far beyond the battlefield. Suleyman Askeri, the Ottoman commander, blamed the defeat on the Arab irregulars who had failed to support his regulars. The humiliation consumed him. He would ultimately take his own life over the loss. Major George Wheeler of the 7th Hariana Lancers, who had led one of the failed early attacks against the irregulars, was awarded a posthumous Victoria Cross for his actions during the battle -- a recognition that the fighting at Shaiba, even in its failed moments, demanded extraordinary courage. The battle's significance was strategic as well as personal. It was the last time Ottoman forces would seriously threaten Basra. After Shaiba, the initiative in Mesopotamia shifted permanently to the British.

Shaiba changed the political landscape as much as the military one. Arab tribes that had joined the Ottoman cause or remained neutral began distancing themselves from Constantinople's war. Later, revolts broke out in the holy cities of Najaf and Karbala upriver -- acts of defiance against Ottoman authority that would have been unthinkable before the defeat at Shaiba demonstrated the empire's weakness in Mesopotamia. For the British, the victory confirmed their hold on Basra and the vital communications and industrial hub it represented. The Mesopotamian campaign would continue for three more years, with terrible setbacks ahead at Kut al-Amara and elsewhere. But the question of whether the British could be pushed out of southern Iraq was answered definitively in the flooded fields southwest of Basra, where thirsty soldiers with fixed bayonets charged across open ground and broke an empire's counterattack.