'Wop' was a US counter-offensive in Tunisia by Major General George S. Patton’s US II Corps to retake Gafsa and El Guettar, which had been seized by the Germans in 'Morgenluft' (i) (17/23 March 1943).

It was on 6 March that Patton took over command of the II Corps from Major General Lloyd R. Fredendall after the corps' major reverse in the Battle of the Kasserine Pass, and Patton’s forceful leadership immediately started to revitalise the formation. The II Corps now consisted of Major General Terry de la M. Allen’s 1^st Division, Major General Manton S. Eddy’s 9^th Division, Major General Charles W. Ryder’s 34^th Division and Major General Orlando Ward’s 1^st Armored Division, but of these the 9^th and 34^th Divisions had each detached one regiment for duty elsewhere.

General the Hon. Sir Harold Alexander, commanding the Allied 18^th Army Group, was convinced that as a result of its poor performance in the fighting at Kasserine Pass and Sidi Bou Zid the II Corps was in need of more training before it could again be committed to any major operation, and Patton was therefore allocated a limited task. This was the diversion of Axis forces, from the front along the Mareth Line defences in south-eastern Tunisia currently being faced by General Sir Bernard Montgomery’s British 8^th Army, by the recapture of Gafsa for a supply point; and the undertaking of a reconnaissance toward Maknassy, being careful to avoid becoming heavily engaged. Patton naturally wanted to drive all the way to the coast, but Alexander remained firm.

Now heading Heeresgruppe 'Afrika', Generalfeldmarschall Erwin Rommel had recommended withdrawal of Generale d’Armata Giovanni Messe’s Axis 1^st Army to Enfidaville to permit a more efficient employment of his surviving forces, but Generalfeldmarschall Albert Kesselring, the Oberbefehlshaber 'Süd', was fully supported by Adolf Hitler in refusing this recommendation, and directed a stand against the 8^th Army at the Mareth Line. By 20 March, Montgomery was ready to attack, and by this date Patton, who had found Gafsa undefended on 17 March, was now probing to the east and so pinning Generalleutnant Friedrich Freiherr von Broich’s 10^th Panzerdivision on his front. In 'Pugilist-Gallop' at Mareth, Lieutenant General Sir Oliver Leese’s British XXX Corps was to make the main attack on a narrow front, while Lieutenant General Sir Bernard Freyberg’s New Zealand Corps swung south around the mountains and then moved up across the Axis rear. Behind a tremendous artillery bombardment, the XXX Corps' moonlight attack made some progress, but counterattacks by Generalleutnant Willibald Borowitz’s 15^th Panzerdivision finally drove it back on 23 March.

With the failure of his main attack to breach the line, Montgomery showed great command flexibility and abandoned his original plan, instead sending Lieutenant General B. G. Horrocks’s British X Corps headquarters with Major General R. Briggs’s British 1^st Armoured Division to reinforce the New Zealand Corps, which was deep in the Axis rear by 22 March and had already begun to siphon off Axis strength from the main position. On 26 March a combined offensive by the New Zealand Corps and the X Corps attack broke through Axis defences to the south-west of El Hamma, but the Italo-German forces evaded encirclement and withdrew toward Wadi Akarit.

Meanwhile, Patton’s attacks in the area of El Guettar and Maknassy had so concerned Generaloberst Hans-Jürgen von Arnim, commanding the 5^th Panzerarmee, that he ordered the 10^th Panzerdivision to counterattack. The 1^st Division handily repulsed this attack on 23 March. The 9^th and 34^th Divisions were now released to Patton, who was instructed to break out on the coastal plain west of El Guettar and Fondouk. His attacks made little progress against stubborn resistance. But when Montgomery lunged forward at the Wadi Akarit on 6 April, Messe withdrew his 1^st Army toward Enfidaville, and this meant that the link of the II Corps and the 8^th Army in the area to the north of El Hamma trapped no Axis forces. On 8 April the 34^th Division, temporarily under British command, renewed the attack on Fondouk, but made little progress. By the time Major General C. F. Keightley’s British 6^th Armoured Division of Lieutenant General K. A. N. Anderson’s Allied 1^st Army finally made contact with elements of the 8^th Army on 12 April, the great bulk of the Axis forces had escaped skilfully.