The squadron became part of the Desert Air Force's newly formed No. 239 Wing on 1 March 1942, serving alongside one Australian squadron, No. 3, and two RAF squadrons, Nos. 112 and 250 Squadrons. No. 450 Squadron's main roles—escorting daylight raids by Douglas Boston bombers, and ground-attack missions in support of the Eighth Army—were hazardous and resulted in relatively heavy losses. From 26 May, as Rommel launched an assault on the Gazala–Bir Hacheim line, all Kittyhawk units began to focus on the fighter-bomber role rather than air-to-air combat, to support retreating Commonwealth forces. On 29 May, No. 450 Squadron claimed two Junkers Ju 87s and a Messerschmitt Bf 109, for the loss of three pilots killed, including Shaw. Flight Sergeant Don McBurnie, the squadron's highest-scoring pilot with five solo victories and one shared, claimed his final "kill" on 4 July 1942 when he shot a Messerschmitt Bf 110 into the sea following a bombing mission on airfields west of Daba.