On the morning of Wednesday 30 September he took off with Oblts Schlang and Poettgen to carry out a sweep in the Cairo area. Marseille was flying a new 'G' model Bf 109 and, on returning from the uneventful patrol at about a height of 4,500 feet, a glycol line broke and set the oil cooler on fire. As his cockpit filled with smoke, he opened the small windscreen ventilator to clear it. This had little effect, and his companions pleaded with him over their radios to bale out. However, the trio of Bf 109s were still three minutes flying time away from the safety of the German lines, and Marseille had no desire to become a PoW. The cockpit continued to fill with acrid smoke, preventing him seeing or breathing properly; his wing man tried to guide him, but it became obvious that the 109 was doomed.
As soon as the trio crossed the line, Marseille flicked his aircraft on to its back, jettisoned the canopy and tried to drop clear, but he had not realized that the aircraft was in a nose-down attitude and centrifugal force held him firmly in place. He eventually struggled free, but as he fell was knocked unconscious by a massive blow to the left side of his chest from the fin that carried the 158 kill markings. He never recovered to deploy his parachute and fell to his death four miles south of Sidi Abdul Rahman.
At his funeral on 2 October in the cemetery at Derna, Neumann said, 'A restless heart is now resting, but we fly on. May the fighting spirit of Marseille inspire all men of JG 27 '.
His final score included 101 Curtiss Tomahawks and Kittyhawks, 30 Hurricanes, 16 Spitfires and 4 bombers ... Adolf Galland was moved to call him 'the unrivalled virtuoso among fighter pilots of the Second World War'.