Manchester United's 3-2 defeat to Brighton last Sunday was one of the club's worst performances under Jose Mourinho since he took charge in 2016.
To rub salt into the wounds, United's disappointment was heightened following Manchester City's emphatic 6-1 win over Huddersfield earlier on in the day.
Despite it only being the second game of the season, fans have been quick to vocalise their opinions on the manager with many calling for the Portuguese to leave or be sacked.
United's woes can, however, not be pinned down to one reason. Here are three potential causes for the loss: