The only fair comparison to make between a DF and recumbent would be to take identical twins of the same fitness level and ability. Place them on each or the respective machines and race them (assuming they they had the same level of training and competence on their bikes). Even then there would be differences depending on how each of the twins felt on the race day.
I think I could beat an upright rider of the same age and ability as myself under most conditions, except perhaps steep uphills. Even on the steep uphills, I may give the upright a good run for his money if the respective bikes were the same weight (give me the carbon M5 Pleeez!). On the level the upright would have no chance at all.