While we don’t like to acknowledge it, the Soviet Army did the heavy lifting in World War Two when it came to grappling with the German Army. The battles in the east, the Ost Krieg, the Germans called it, were larger than anything in the West. Over 80% of German soldiers killed in World War Two were killed by the Soviets and over 80% of the land fighting took place in the Soviet Union. According to Soviet Home Front: 1941-1945:
This is a staggering statistic and quite true. We are so smug in this country about our military prowess and so ignorant of our own military history. The US as a nation believes we can go around and kick ass and do whatever we want. After all, in World War Two we took down the Japanese and the Germans. But we didn’t beat the hell of the Germans. The Soviets beat the hell of the Germans.
[Source: Soviet Home Front: 1941-1945 by John Barber and Mark Harrison.]