The specific units involved were, according to Imperial War Museum curator Chris Plant:
The Allied front line in this sector was arranged as follows: (from north to south): 2nd Battalion The Rifle Brigade; 2nd Battalion Kings Royal Rifle Corps (60th); a composite regiment of 10th Hussars including a Rifle Brigade Company; the 4th Light Armoured Brigade and 1st Battalion Kings Royal Rifle Corps (60th) along with a composite regiment of the 4th / 8th Hussars. These units were backed up by the artillery of the 3rd and 4th Regiments of the Royal Horse Artillery. Opposing them (again from North to South) were the German 90th Light Brigade, the Italian XX Corps, the Deutche Afrika Korps (DAK) formed by the 21st and 15th Panzer Divisions and a combined German and Italian Reconnaissance Group.
In an effort to bypass the British position and cut it off from its base in Egypt, the Axis forces attacked the weaker Southern sector of the British line. Rommel's main offensive force then struck north. Decrypted German Enigma signals gave Montgomery the time and place of the assault, enabling him to put batteries of artillery in position on the Alam el Halfa ridge to destroy the German tanks.
On August 31, Rommel's troops were halted after bitter fighting and heavy losses just to the southwest of Alam el Halfa. Another assault on the ridge on September 1 was repulsed. By now the Axis forces were suffering from supply shortages especially fuel, and on September 2 Rommel ordered a withdrawal by stages. Both sides clashed again on the night of the September 3 when the retreating Germans were attacked by New Zealand units. All the while, the Desert Air Force were adding to Rommel's supply problems by attacking his supply columns.
By September 5 the Axis forces had reached the eastern side of the old British minefields. Sporadic fighting continued on September 6, with the British making small gains against the Germans and on September 7, with a lull in the fighting, both sides regrouped and the battle ended. The Germans had gained about five miles of the southern Alamein front.
The First Battle of El Alamein 1–July 27, 1942 was a battle of the Western Desert Campaign of World War II, fought between the German–Italian Afrika Korps commanded by Erwin Rommel and the British Eighth Army, commanded by Claude Auchinleck.
Following the defeat at the Battle of Gazala in June 1942, the Eighth Army had retreated from Mersa Matruh to the Alamein Line in Egypt, a 40 mile (60 km) gap between the town of El Alamein on the Mediterranean coast to the north and the Qattara Depression in the desert to the south.
A second attempt by Rommel to bypass or break the Commonwealth position was repulsed in the Battle of AlamHalfa in August, and in October the Eighth Army, now commanded by Bernard Montgomery, decisively defeated the Axis forces in the Second Battle of El Alamein.