At the outbreak of World War II on 1 September 1939, Mölders' "Staffel" was stationed in the west protecting Germany's border in the Mosel–Saar–Pfalz region. On 8 September 1939, Mölders' fighter suffered an engine failure; he crash-landed, flipping the aircraft over and injuring his back. The injury kept him out of combat for several days. He returned to flying on 19 September. The following day, between Contz and Sierck, at the apex of the "Dreiländereck", over the three borders area, he shot down his first aircraft of the war, a Curtiss P-36 (according to other historians, it was one of a trio of French Hawk H-75As), of "Groupe de Chasse" II/5 (Sgt Queginer bailed out). Thanks to that victory, he earned the Iron Cross 2nd Class.