If you had said the words ‘seven nil’ to Manchester United supporters before Tuesday’s Carabao Cup meeting with Barnsley, it would have been enough to spark a bout of PTSD. This time, however, it was Erik ten Hag’s side who found themselves cracking open a cold can of 7Up and toasting a roasting. Manchester United stormed to their biggest win of the Ten Hag era as they put Barnsley to the sword at Old Trafford. For so often, a criticism aimed this Red Devils side is that they have a tendency to let the opposition off the hook and make poor decisions in the final third. A case in point; no team…