How did the Germans react to the renewed Allied strength in battle following the addition of American troops?

If it is about world war I, then the Germans was battered and starting to lose hope after the renewed strength of the Allied army and the lose of an already large quantity of man made the German army almost depleted with reserves. If it is world war II it would be the same with world war I but the German army was still able to match and fought the allied forces for some years before being defeated.