By Matthew Cooper Danny Murphy believes Manchester United must sack Erik ten Hag following their 3-0 defeat to Bournemouth at Old Trafford on Saturday. Dominic Solanke, Philip Billing and Marcos Senesi all scored for the Cherries as they earned their first ever away win against United. The result also means that United have now conceded three or more goals at Old Trafford five times in a single season for the first time in 60 years. And Murphy believes that with United “regressing”, they need to get rid of Ten Hag now. “The fact Bournemouth won at Old Trafford and no one is surprised tells you…