Manchester United teenager Kobbie Mainoo started his first Premier League game at Old Trafford and had a night to remember. Erik ten Hag has tried to use Kobbie Mainoo sparingly since he returned to fitness last month. This has meant that Mainoo’s starts have all come away from home, against Everton, Newcastle, Liverpool and West Ham. It has not been an easy run, yet, this is the confidence the manager has in the 18-year-old midfielder. Last night he got his chance to shine at Old Trafford, starting against Aston Villa, and his composed performance helped the team to a 3-2 victory. Mainoo star…