Following a lengthy home leave, Wiese was tasked with the leadership of I. "Gruppe" (1st group) of JG 52 on 11 May 1943. On 13 November 1943, he was officially appointed "Gruppenkommandeur" (group commander) of I. "Gruppe" and at the end of 1943, Wiese was promoted to "Major" (major). His most successful day was 5 July 1943, the first day of the Battle of Kursk, when he shot down twelve enemy aircraft in one mission, a double "ace-in-a-day" achievement. All 12 victories were over Ilyushin Il-2 Sturmovikground attack aircraft and took his total to 95 victories. On 17 July 1943, Wiese was credited with his 100th aerial victory. He was the 45th Luftwaffe pilot to achieve the century mark. In end July, Wiese had fallen sick and had to go to a Bad Wiessee for treatment. During his absence, "Hauptmann" Gerhard Barkhorn, the commander of 4. "Staffel", temporarily led I. "Gruppe" from 4 to 30 August.