The 2/13th Battalion was fortunate to only have had 98 casualties, a number that included three officers, in the battle at Er Regima on 4 April 1941. Of those, five men were killed. The other unit engaged at Er Regima, the 51st Field Regiment, had one man killed and five "injured" as the Official History says. One of their officers was missing, possibly a prisoner.
The German attack on Er Regima was the only German action on 4 April. The German armored unit, the 5th Light Division, was held back. Their British counterparts, the 2nd Armoured Division, had a bad day on 4 April. A column of vehicles carrying fuel was attacked by German aircraft and the entire column was destroyed. They had met more vehicles with fuel and joined with them, but they were all lost. By evening, the 5th RTR was reduced to nine tanks. The 6th RTR only kept their best Italian tanks and scrapped the rest. They were now down to just nine tanks, as well. The 3rd Hussars, now "14 miles northeast of Msus", were also abandoned their worst tanks. To the south, A Squadron of the LRDG drove south to the Trigh el Abd. They then drove to Bir Ben Gania. They reported back that they had not seen any sign of the enemy forces. A German reconnaissance aircraft overflew them that evening.
While all this was happening, the 3rd Indian Motor Brigade moved to Mechili. The only building at Mechili was an old fort that was very weak. The importance of Mechili was the good water supply. The place had no other value. The 3rd Indian Motor had three completely motorized cavalry units. They only had small arms, apparently, but were highly mobile. This is based on the account in Vol.III of the Australian Official History.