It’s either a testament to Kobbie Mainoo’s remarkably well-rounded skillset – or a rather damning indictment of Manchester United’s squad building – that the 18-year-old is the closest thing Erik ten Hag really has to a ‘complete’ midfielder. It is, Mainoo aside, a Manchester United engine room full of specialists but light on all-rounders. Bruno Fernandes is an elite creator but often struggles to influence proceedings outside of his favoured number ten role. Christian Eriksen remains excellent in possession but poor without it. Casemiro, the opposite. Scott McTominay is one of the few consis…