it is not just the raw ability and potential of the Manchester United starlet that has marked him out as a potentially generation-defining talent at the Premier League giants. It is his mentality too. A rock-solid self-discipline, and a ravenous hunger to improve. Even after opening his Old Trafford account in a moment mere mortals can only dream of – a glorious finish against none other than Manchester United’s arch rivals Liverpool – Kobbie Mainoo was reluctant to get too carried away, insisting that the failure to hang onto yet another lead tempered that excitement somewhat. Kobbie Mainoo w…