Erik ten Hag's reds were outclassed tactically by Roberto De Zerbi's seagulls as their impressive 31-match unbeaten run at home came crashing down as a result of Brighton's brilliance. Superb goals from former red Danny Welbeck, Pascal Gross and summer signing Joao Pedro were enough to make it three losses out of the first five games of the season for United.
United started the game well, and for the first twenty minutes of the game ten Hag's formational tweak to a 4-1-2-1-2 diamond shape seemed to counteract Brighton' ability to play through the middle of the pitch. Having the extra body in midfield in Scott Mctominay also allowed United to win the ball back higher and create chances.
One of these chances resulted in a Rasmus Hojlund debut goal which was ultimately disallowed due to the ball being deemed to have gone out of play prior to Marcus Rashford cutting the ball back to Hojlund for the tap-in.
Brighton kept to their principles however, and ended up finding a way to play through the middle with Welbeck receiving upfront, who was able to lay off the ball to Simon Adingra on the wing and receive the ball once again in the middle of the box for a goal to give Brighton the lead against the run of play.
The second half saw Brighton steadily gain more control of the game as the minutes ticked by, only ceasing possession when United counter-attacked. The more possession Brighton gained, the more chances they managed to create for themselves, and thus resulted in an expertly taken goal from Gross in the 53rd minute, and a dagger from Pedro in the 71st to cap off a tactically astute 2nd half performance from the seagulls.
Here are four things we learnt from the game.
United's diamond formation can work very well with the right profiles
On paper, it seemed like United may persist with Bruno Fernandes trying his best to have any sort of impact on the game from the right hand side, while Mctominay, Casemiro and Christian Eriksen slugged it out in the middle of the park. This wasn't the case however, as from the get-go United setup with Fernandes just behind the two forwards in Rashford and Hojlund, with Eriksen and Mctominay just behind the skipper as the two holders, and Casemiro behind them as the deepest midfielder of the four.
The fruits of a setup like this were evident in the first twenty minutes of the game where United pressed like their lives depended on it, making it easier for them to win the ball back high up. It was clear that having the extra body in Mctominay was helping Casemiro too, as it allowed the Brazilian to always sit just north of zone 14 ready to deal with any attacking threats through the middle.
However, there were a few notable flaws with the system, and the majority of these issues traced back to personnel. In comparison to other teams in the league (especially the big 6 teams) United seriously lack seriously athletic profiles in the middle who can run profusely for 90 minutes, and it showed when United constantly failed to defend wide spaces when Brighton counter-attacked or built up from the back. United will continue to be unable to make the jump to elite status if the teams athletic floor is still average.
Another flaw in this new system is the lack of technical ability in comparison to other teams in the league, which was evident yet again when United were outclassed by one of the most technically gifted teams in Europe right now. Today and so far this season in general United's first phase buildup hasn't been bad at all, but it could be so much better if they added more first phase conductors to the likes of Lisandro Martinez, Eriksen and Diogo Dalot.
A silver lining from the performance today is that if you replace Casemiro and Mctominay with Mason Mount and Sofyan Amrabat (who are currently out injured), the box midfield's quality drastically improves.
Lack of concentration is still an issue for United
As the game entered its latter stages it became clear that United players were growing tired, and this affected their concentration levels. For a team that just a few years ago used to thrive in the 2nd half of games, United now are notorious for their massive quality drop-offs in the second half of games.
This could be because of the aforementioned athletic problem that United have yet to solve in years, meaning that if they can't fight for the ball they allow opposition who can keep the ball better to circulate possession until they make a mistake.
It could also be due to the lack of technical quality that United possess in their first and second phases, which once again comes back down to personnel. Victor Lindelofs ball progression wasn't great today and once Martinez started to lose the ball more after Brighton's third goal it only made it much easier for Brighton to win the ball back high up.
There was also an abundant lack of concentration defensively, as United's defenders on all three occasions were cut open too easily in and around their own box - Raphael Varane (who is an eminent box defender) was greatly missed today.
Brighton's game plan was ultimately successful
Brighton never once abandoned their principles during the game and this was key to their eventual success. Brighton were able to weather United's early storm and once it had passed they settled into their usual shape, building up in a three and sending the ball wide when they couldn't play through the middle.
They were patient in the buildup and didn't rush their attacking play as they were aware of the obvious threat United posed on the counter. United's dangerous forwards prompted Brighton to fill their box with players whenever United were attacking, meaning that on numerous occasions whenever United got in behind Brighton's back-line, United struggled to test Jason Steele due to the sheer amount of bodies in the box blocking shots.
It truly is impressive that even after making six changes to their starting eleven, Brighton still managed to maintain a level of technical brilliance that proved too assured to handle for the red devils. Once Brighton had found a chink in the armour of United's diamond setup, they also ensured that United couldn't execute a plan b.
Steele, Lamptey and Gross were key to Brighton's triumph
When analysing Brighton's games it is always difficult to pick standout players because they always play like a well-oiled machine - each and every player understands their role wholeheartedly and they all work for each other. However today, the player of the match could've justifiably been awarded to any of Steele, Tariq Lamptey or Gross.
Gross was untouchable in the middle of the park, proving quintessential to Brighton's ability to circulate possession so well. The most impressive thing about Gross today was the high volume in which he was passing, having 112 touches of the ball and completing 98% (!) of his passes. His dominant performance was capped off with a deserved goal which was confidently taken.
Steele was very important in Brighton being able to retain possession, as is what's expected of modern goalkeepers. He completed the majority of his passes and long balls and whenever he was pressed he didn't break a sweat, seriously improving the efficiency of Brighton's first phase buildup.
It was a big ask for Lamptey to play as an inverted fullback at Old Trafford but as always with De Zerbi there's a method to his madness, and once again his risk-taking was rewarded. Lamptey was able to progress play very well from the left hand side and formed a good understanding with Kaoru Mitoma, whom he almost assisted late in the second half. Lamptey's final third play was sublime and was thoroughly deserving of two assists.
