On 15 September 1940, also known as the Battle of Britain Day, III. "Gruppe" engaged 20 to 30 Royal Air Force (RAF) fighters south of London. In the resulting combat, Wilcke claimed the destruction of his second Hurricane. Two days later, on a mission that began at 4:35 pm, Wilcke achieved his ninth victory, another Hurricane. He claimed his tenth victory, again a Hurricane, on a mission targeting the London area that took off at 11:15 am on 20 September. On the last day of September 1940, he claimed two more victories to bring his total to 12; the action took place during his second mission of the day, which began at 1:45 pm, escorting Dornier Do 17s to London. In combat with RAF Spitfires, Wilcke claimed his 13th victory at 11:45 am on 10 October 1940, his final of the Battle of Britain. In recognition of these achievements he was awarded the Honor Goblet of the Luftwaffe () on 1 April 1941.