September 15 - Watford vs Manchester United (Away)
Watford are the surprise package of this season so far and currently find themselves in the top four, with a perfect record of 3 wins from 3 games.
Javi Gracia has brought back the traditional 4-4-2, therefore, getting the best out of his team and his star player, Roberto Pereyra. They've been playing some impressive football this season and if they continue this early season form, the Hornets can end up in the European competitions next season.
Manchester United should view them as tough as any other top-6 game and while Watford are high on confidence, Mourinho can hope to outsmart Gracia with the plethora of attacking and creative options and sneak out a victory on the road.
By this time, Mourinho may have his whole squad back from injuries and a range of formations and options to choose from.