Kammala jumla mai zuwa: A cikin hunturu na 1940/41, Ribbentrop ya matsa lamba sosai ga Masarautar Yugoslavia don sanya hannu kan Yarjejeniyar Tripartite, duk da shawarar da Ofishin Jakadancin Jamus a Belgrade ya bayar cewa irin wannan aikin zai iya haifar da hambarar da Yarima Paul, mai kula da Yugoslav. Manufar Ribbentrop ita ce ta sami haƙƙin wucewa ta ƙasar wanda zai ba wa Jamus damar mamaye Girka. A ranar 25 ga Maris, 1941, Yugoslavia ba tare da son rai ba ta rattaba hannu kan Yarjejeniyar Tripartite; washegari sojojin Yugoslavia sun hambarar da Yarima Paul a cikin juyin mulki mara jini. Lokacin da Hitler ya ba da umarnin mamaye Yugoslavia, Ribbentrop ya yi adawa, saboda ya yi tunanin Ofishin Harkokin Waje zai iya cire shi daga mulkin Yugoslavia. Kamar yadda Hitler ya yi fushi da Ribbentrop a kan adawarsa ga mamayewa, ministan ya kwanta a cikin kwana biyu masu zuwa. Lokacin da Ribbentrop ya farfaɗo, ya nemi damar da za ta ƙara tasirin hukumarsa ta hanyar ba Croatia 'yancin kai. Ribbentrop ya zaɓi Ustaša ya yi mulkin Croatia. Ya sa Edmund Veesenmayer ya sami nasarar kammala tattaunawa a watan Afrilu na 1941 tare da Janar Slavko Kvaternik na Ustaša kan samun jam'iyyarsa ta mallaki Croatia bayan mamayewar Jamus. Da yake nuna rashin jin dadinsa game da Ofishin Jakadancin Jamus a Belgrade, wanda ya ba da shawara game da tura Yugoslavia don sanya hannu kan Yarjejeniyar Tripartite, Ribbentrop ya ƙi barin ofishin Jakadancin na Jamus a baya kafin Jamus
sun yi wa Belgrade bam a ranar 6 ga Afrilu, 1941. An bar ma'aikatan don tsira da tashin bama-bamai kamar yadda zai yiwu.