 By late on the 19th , Austrian and French soldiers had been skirmishing at outposts for more than 30 hours , with the action growing increasingly intense . In the early hours of the 21st , General Lefebvre informed Jourdan that the Austrians were attacking all his positions , and that the general engagement would begin shortly . After 24 hours of fighting , Austrian forces pushed Lefebvre and Saint Cyr 's troops back to the Pfullendorf heights . Although sappers blew up the primary bridge over the Ostrach river , the Austrians managed to ford the stream anyway . They nearly outflanked General Saint Cyr 's forces on the right flank , did outflank Lefebvre 's forces in the center , and cut off a portion of the southern flank from the main body . Saint Cyr 's troops barely managed to pull back before being fully cut off . Finally , General Friedrich Freiherr von Hotze , marching north with 10 @,@ 000 men , from Feldkirch , threatened Ferino 's First Division from the south . 
