I just finished a battle (delay, 11/41 Stalingrad) where I got my butt handed to me on a silver platter. I had to pull back all of my forces before they were decimated. Even with that, I had over 50% loses in my core.
The worst bit was when a unit would get pinned down right in front of the advance or right next to an immobalized enemy tank. I couldn't just leave them there to get slaugthered (there's my attachment of my units showing) so I mounted rescue missions. Overall, I tried rescuing 6-8 different squads and I only had 16 total. It was a fun battle, even if I did lose. As always learned a lot. (I'll be posting it in "letters from Stalin's City").
I took twice as many of theres as they took of mine. Ha! I was very happy with that marginal defeat!