Manchester United’s players left Old Trafford shattered but proud as the team twice came from behind to knock Liverpool out of the FA Cup. So often through the post-Sir Alex Ferguson era, there have been criticisms of the team’s desire, and quality. At the weekend against Liverpool, there could be no criticising of how this set of players fought their way back into the game. It wasn’t pretty, but they managed it. Erik ten Hag had shifted players around into unusual positions, pulling out everything he had at his disposal, and every single footballer in a Manchester United shirt gave all they h…