Berikut daftar pemain unggulan yang kalah di hari keempat Kejuaraan Dunia 2021.
MS - Kanta Tsuneyama (Jepang/9) vs Hans-Kristian Solberg Vittinghus (Denmark): 21-11, 13-21, 17-21
WS - Line Christophersen (Denmark) vs Busanan Ongbamrunphan (Thailand/11): 3-1 (retired)
WD - Ashwini Ponnappa/Reddy N. Sikki (India) vs Liu Xuan Xuan/Xia Yu Ting (China/14): 21--11, 9-21, 21-13
WD - Ng Tsz Yau/Yuen Sin Ying (Hong Kong) vs Pearly Tan/Muralitharan Thinaah (Malaysia/13): 10-21, 21-12, 21-11