Well the Nazis started off hard and the Russians did what they always do and retreated burning crops and shit so the invaders would have nothing to live on as they advanced. The nazis made it to Stalingrad and Leningrad and got bogged down and finally the Russians encircled them and kicked their ass.

Not that it was the best outcome but it was pretty much what they did when Napoleon invaded. The Russians have two advantages, their country is huge and winter comes once a year.