I don't think the problem is in defense. Utd often lose by the odd goal. Mistakes get made each game. The problem is the lack of vision, speed, infiltration etc coming from midfield. If that gets sorted out I think the confidence will go up. Nobody will mind a defensive laps if the team gets forward with intent, creating chances and scoring goals. Now it's nervewecking for the team, a mistake gets punished and one mistake for this Utd is often the margin between winning and losing. Liverpool concedes goals every game too so that means mistakes are made but the confidence there is sky high and they keep winning as a result.