On 22 June, the "Geschwader" crossed into Soviet airspace in support of Operation Barbarossa, the invasion of the Soviet Union, which opened the Eastern Front. III. "Gruppe" took off on its first mission at 3:20 am with the "Gruppenstab" (headquarters unit) and 7. "Staffel" targeting Soviet airfields at Alytus and Oranji. Wilcke shot down three Polikarpov I-15 biplane fighter aircraft. The second mission of the day by III. "Gruppe" was a Stuka escort mission to Grodno at 6:00 am, during which Wilcke claimed another victory. He led another attack at 4:10 pm; while strafing airfields, he claimed his fifth aerial victory of the day, an "ace-in-a-day" achievement, taking his total to 18.