If a battle is lost, the general should retreat and come back with another army. That's smart, not cowardly. A Roman generla fighting like a Sweboz warchief to death? Noooooo
I bet you the German warlord would drool at the offer/chance...

There are a few examples of Roman nobles becoming heroes be engaging Gallic champions in single combat and (of course as Romans wrote our histories of such), thus becoming famous heroes.