Angered by this comment, Oesau took off in a Messerschmitt Bf 109 G-6/AS "Green 13" ("Werknummer" 20601—factory number) from Paderborn despite a high fever. Leading three aircraft of the "Geschwaderstab", the schwarm broke formation over the Ardennes as it approached the bombers. In the dogfight Oesau's wingman reported damage to his machine and he was ordered to break off. Left alone, Oesau faced P-38s and possibly P-51s as well. According to "Major" Hartmann Grasser, "Gruppenkommandeur" of III./JG 1, who was on the same mission, there were five P-38s facing Oesau.