Mezue ahịrịokwu na-esonụ: Mgbe Operation Barbarossa, mwakpo ndị Germany nke Soviet Union, bidoro na 22 June 1941, Yermolkin lụrụ ọgụ na Southwestern Front na ndị otu ya. Dị ka akụkụ nke ndị agha nke iri abụọ na isii, nkewa na ndị agha ya malitere agha na mpaghara Drogobych. N'oge agha Border na 25 June 1941 dị ka akụkụ nke ndị agha ahụ, ngalaba ahụ malitere
mbuso agha na mpaghara Brody na Dubno, ma mesịa n'ọgụ kpụ ọkụ n'ọnụ laghachiri Proskurov na Vinnytsia. Mgbe ahụ-Major Yermolkin merụrụ ahụ site na shrapnel n'oge ọgụ na mpaghara Radzivilov na 28 June. N'ọnwa Ọgọstụ n'oge Agha nke Kiev, a họpụtara ya onye isi nke 300th Motor Rifle Regiment nke 7th Motorized Division, na-eduga ya n'ọgụ kpụ ọkụ n'ọnụ na ndịda nke Kiev dị ka akụkụ nke 26th Army. E jidere Yermolkin na gburugburu na Septemba mana o jisiri ike laghachi na Soviet na Ọktọba, mgbe nke ahụ gasịrị, ọ natara iwu nke 680th Rifle Regiment nke 169th Rifle Division, nke na-alụ ọgụ dị ka akụkụ nke 38th Army nke Southwestern Front na mpaghara Volchansk. Site na Disemba ọ nyere iwu na 584th Rifle Regiment nke 199th Rifle Division nke ndị agha. Na July 1942 Yermolkin ghọrọ osote onye isi nke 304th Rifle Division nke ndị agha n'oge ọrụ Donbass Defensive.