24 July marked the beginning of a period in the Combined Bomber Offensive which was referred to as "Blitz Week". As part of the offensive, the next day, U.S. Martin B-26 Marauder bombers attacked the Ghent coke furnaces. I. "Gruppe", led by Borris, was scrambled at Woensdrecht to intercept the attack on Ghent. The "Gruppe" engaged the escorting fighters and claimed four Spitfires destroyed plus a further Spitfire damaged, without loss. Following this aerial battle, Borris was credited with two aerial victories over two No. 165 Squadron Spitfires claimed shot down north of Ghent at 15:04 and 15:09 respectively. The USAAF targeted the German aircraft industry on 17 August 1943 in the Schweinfurt–Regensburg mission. In defense of this attack, Borris, who had returned to his unit, claimed the first of 60 B-17 bombers lost by the USAAF that day. At 11:30, he had shot down a B-17 from the 94th Bombardment Group which came down east of Deest.