Count Keyserling (then with the Prussian Silesian "national" cavalry regiment) describes a nice example for a duel between (small) armies before the main event, here beetween a French carabinier (?) officer and an officer of the Prussian Brandenburg hussar regiment (during the raid of GL Thielmann in the autumn campaign, 1813):

https://books.google.de/books?id=5J5DAAAAcAAJ&pg=PA80

Keyserling calls the duel tragicomic, attributing to the French officer a "rodomontade" before the duel...

Regards, Thomas