Something else that has not been mentioned is that Russia was running out of military manpower. Yes, the Russian Army was huge. However, their losses had been so enormous that they were starting to scrape the bottom of the barrel for new recruits - prisons etc. They would have had a hard time maintaining their armed forces at their May, 1945 levels. I've heard reports that of males born in the USSR in 1922 or 1923, NOT ONE survived the war. Also that the Russian death toll, long believed to have been a bit over twenty million, was more like forty million, including civilians. Stalingrad alone cost them a full million dead.
Also, at the end of the war, the US was the only major power whose economy was not on the brink of collapse.
If you're just talking about Patton - and Patton only - vs the USSR though, I think I'd put my money on the USSR.
