Manchester United were stunned by Hull City in their opening fixture of the 26/27 season as the newly promoted side beat the Red Devils 2-0. 

Inside 13 minutes, Manchester United were handed the first big chance of the game. Luke Shaw lofted in a cross that Nabil Fekir missed, and the ball fell to Bryan Mbeumo, who volleyed it and forced Konstantinos Tzolakis into a big save.

However, five minutes later Hull took the lead after a set-piece fell to Ollie McBurnie, whose shot Lammens saved, but no one was there to pick up the second ball. Semi Ajayi reacted quickest and smashed the ball home from close range.

Set pieces proved to be United's downfall once again when Regan Slater whipped in a dangerous free-kick from the right for Mendy to thump past Lammens. 

Here are five things we learnt from this disasterous start to the season.

The alarm bells had been there across pre-season with many of the goals United conceded coming from either low or whipped-in crosses where players were caught napping. 

Yet again, these glaring issues came to the fore with the club conceding from two set-pieces and very much could have conceded a third when McBurnie was unmarked for a header early on in the game.

It's not just the fact that this is seemingly a blueprint for how we concede. It is the lack of urgency the players had. Especially for the first goal, there was no one anywhere near Ajayi, with the comical image of Harry Maguire looking like he was marking Mbeumo. 

While these errors are more issues with players not being switched on and physically not being able to match Hull, this will be a major headache for Michael Carrick.

What seemed to be a coincidence at first is now turning into a scary reality, with United having a glaring difficulty in playing against three-at-the-back formations. 

It was less so in terms of chances being hard to come by, as the likes of Mbeumo and Patrick Dorgu did have opportunities. It was when we were defending that we looked vulnerable. 

The use of wing-backs that dominate the space on the wings due to the use being so compact in central areas and full-backs tucking in gives the sides so many chances to be dangerous with their crosses. 

It seemed almost a carbon copy at times, in terms of the flaws Hull exploited, of the ones AC Milan exploited in pre-season. Another huge headache for Carrick, especially when the team is out of possession.

This is something that everyone seemed to understand, but it was definitely confirmed today, and Patrick Dorgu is not someone who can regularly be deployed on the wing.

In games where there is lots of space, United are in transition, and Dorgu can leverage his physicality and athleticism, where he is a big threat. But in games like this, and in most games where United will be up against teams looking to minimise space for players, his weaknesses will be exposed.

While he does not usually drop really bad games, this was by far his worst game in a United shirt. Every attack which went down the left-hand side collapsed, whether it was due to a heavy first touch, Dorgu taking too many touches instead of crossing the ball or just poor finishing. His substitution at half-time was indicative of this performance.

When Rashford came on, he offered so much more without being spectacular. If Sesko is not playing and Cunha is forced away from the left, then Rashford should be the player to take up that role.

This can easily be applied to the left-back, with Shaw struggling in the game and continuing to show defensive deficiencies. However, the lack of a number nine until Benjamin Sesko came on seriously hindered United. 

Whenever the Red Devils were in positions to cross the ball, the lack of players in the box, let alone the lack of movement, was painful to see. And when the ball was whipped in there, the chances were squandered. 

Cunha was constantly dropping deep or into wide areas, rather than trying to bypass any of the back three or making constant runs. When Sesko came on, even when he was not found, you could see that every opportunity he had, he made the run. 

This is another massive concern for when the club are without the Slovenian. 

Carrick's side really missed Amad in today's game. The Ivorian was slowly getting better and better as pre-season went on, with a dynamic threat that differs from the likes of Mbeumo. 

His 1v1 threat was what was clearly missing, as was his ability to knock the ball off the opponent. When Rashford came on, you could see time and time again that when he took his man on, he caused chaos before sending the ball into the box. 

Having that from the beginning would have given United so much more aggression going forward, as the team was timid in all areas.

Carrick will be hoping that whatever issue Amad has that it is not a major one.