As will be the case under Erik ten Hag in 2024/25, the Reds kicked things off for the full programme by playing at Old Trafford.
Jose Mourinho's men took on Leicester City and, fresh from finishing runners-up in the previous term, the Reds handed a debut to Fred in midfield.
Meanwhile, the Foxes included Harry Maguire in their ranks, despite speculation United had been looking to sign him in the summer.
United captain Paul Pogba, on a high after winning the World Cup with France, punished a Daniel Amartey handball with a third-minute penalty to get Mourinho's side off to a flying start.