Arne Slot ' s superb start to life at Liverpool continued as Luis Diaz scored twice in a 3 - 0 away win over rivals Manchester United that piled more problems at the door of Erik ten Hag . Liverpool were clinical as Mohamed Salah added a third early in the second half to make it three wins out of three for Slot , but this was a second defeat of the young season for a poor United side , and Ten Hag cut a frustrated figure on the Old Trafford touchline . The issues that dogged United for much of last season and the start of this were ruthlessly exposed as Liverpool cut through United ' s midfield time and again . Casemiro , at fault for two of the goals , was hauled off at half - time but little changed , with Liverpool better in every department . Slot had already enjoyed a 3 - 0 pre - season friendly victory over United in the summer but this win saw him become the first Liverpool boss to beat United in his first competitive meeting since Bob Paisley in 1975 . dpa pa bagSource: The Namibia News Agency