Kammala jumla mai zuwa: An yi wasannin abokantaka da wasannin da ba na gasa ba a lokacin Yaƙin Duniya na ɗaya da na biyu. Gabaɗaya, an buga wasanni 33 tsakanin ƙungiyoyin a Wasannin Yaƙin. Dukansu biyu sun yi rawar gani sosai a gefen matasa, masu ajiya da wadanda ba masu sana'a ba, suna buga wasanni 14 a London Combination tsakanin 1915 da 1919. West Ham ta lashe tara, Millwall uku kuma biyu sun yi daidai. Bayan Yaƙin Duniya na Farko, Associationungiyar Kwallon Kafa ta sake gabatar da Leagueungiyar Kwallon Kafa a Ingila kuma West Ham ta shiga Rukunin Na Biyu don kakar 1919-2020. Millwall ya shiga Rukunin Na Uku na farko a kakar 1920/21, a cikin fadada gasar kwallon kafa na kungiyoyi 44 zuwa 66. A shekara ta 1926 a
An yi yajin aikin gama gari ne daga ma'aikatan da ke kusa da Royal Docks, yawancinsu magoya bayan West Ham ne. Wani labarin da ba shi da tushe ya ce ma'aikatan jirgin ruwa na Millwall da ke tallafawa tsibirin Isle of Dogs sun ƙi ba da goyon bayansu, suna haifar da fushi. A wannan lokacin, Millwall ya riga ya ƙaura daga Isle of Dogs kuma yana wasa a New Cross tsawon shekaru 16.