The Eighth Army first went into action as an Army as part of Operation Crusader, the Allied operation to relieve the besieged city of Tobruk, on 17 November 1941, when it crossed the Egyptian frontier into Libya to attack Erwin Rommel's Panzer Army Africa.
On 26 November the Commander-in-Chief Middle East Command, General Claude Auchinleck, replaced Cunningham with Major-General Neil Ritchie, following disagreements between Auchinleck and Cunningham. Despite achieving a number of tactical successes, Rommel was forced to concede Tobruk and was pushed back to El Agheila by the end of 1941. In February 1942 Rommel had regrouped his forces sufficiently to push the over-extended Eighth Army back to the Gazala line, just west of Tobruk. Both sides commenced a period of building their strength to launch new offensives but it was Rommel who took the initiative first, forcing the Eighth Army from the Gazala position.