As a player Erik ten Hag sold for just £5 million caught the eye in the Champions League, the Manchester United boss must have wondered what he has to do to catch a break. With the Dutchman already fighting for his job – some Manchester United players reportedly believe Erik ten Hag is a dead man walking ahead of tough away trips to FC Porto and Aston Villa – the last thing he needed was further questions over his talent ID. But as Manchester United travel to Portugal without a single senior left-back fit and available, the manner in which Alvaro Fernandez Carreras ripped though Atletico Madri…