Here's an interesting link:
http://www.warbirdforum.com/buff.htm
Since the text below the FW-190 did mention the Finnish war. The Finnish used an obsolete airplane The Brewester Buffalo to its full extent. That and better tactics. Stalin killed off most of the Russian officers before WW2. So there wasn't experienced leadership. I heard 80% of those killed during WW2 were russian. I'm not sure how accurate that source is. Who knows how many Chinese the Japanese killed.
Tom