Allied lapses in communication and Blücher 's overconfidence left Olsufiev 's corps isolated near Champaubert when Napoleon 's army lunged Self_motion from the south to deal it a crippling blow Attack .

The Germans achieved Achieve a total surprise attack Attack on the morning of 16 December 1944 , due to a combination of Allied overconfidence , preoccupation with Allied offensive plans , and poor aerial reconnaissance Scrutiny due Causation to bad weather .

Villa 's defeat was the result of his multiple tactical miscalculations and overconfidence in his much larger , undefeated army 's ability to best Obregón 's army under any circumstances .