Rubuta ci gaba don wannan sakin layi - A watan Yunin 1941 tare da ƙaddamar da Operation Barbarossa, Kleist ya jagoranci rukunin Panzer na 1 a matsayin wani ɓangare na Army Group South - wanda aka ɗorawa alhakin kama Moldavia da Ukraine - kuma ya ga nasara a farkon matakin mamayewa, yana ci gaba da zurfafawa cikin Ukraine. Rukunin Panzer na 1 ya karya ta hanyar Stalin Line, sannan ya ci nasara da ƙungiyoyi biyar na makamai na Soviet 5th Army da 6th Army a yakin Brody
(23 zuwa 30 ga Yuni 1941). A watan Yulin 1941 yayin yakin Uman, rukunin Panzer na 1 ya karya layin Soviet Southern Front, wanda ya haifar da kewaye da lalata sojojin Soviet na 6 da na 12 zuwa kudu maso gabashin garin Uman (a cikin yankin Cherkasy na yanzu). A lokacin Yaƙin farko na Kiev na watan Agusta zuwa Satumba 1941, rukunin Panzer na 1 na arewa daga tsakiyar Ukraine tare da haɗin gwiwar rukunin Panzer na 2 na kudu daga Smolensk ya haifar da kewaye da lalata dukkanin Sojojin Soviet na Kudu maso Yammacin gabashin Kiev, wanda ya haifar da asarar sama da 600,000 ga Red Army. Koyaya, yaƙin ya kasance mai tsada, a lokacin sojojin Jamus suna da rabin tankunan da suke da su watanni uku da suka gabata.