On Friday 1 September 1939, German forces invaded Poland starting World War II in Europe. I. "Gruppe" of ZG 76 participated in this campaign and was based at Märzdorf, present-day Bohdíkov in the Czech Republic, under the command of 6. "Fliegerdivision" (6th Air Division). On 5 September, Falck claimed his first aerial victory when he shot down a PZL.23 Karaś in combat near Dalików. He claimed two further aerial victories over Polish Air Force aircraft on 11 September. He was credited with the destruction of a Fokker F.IX southeast of Biała Podlaska and a PWS-26 southwest of Biała Podlaska.