Man Utd are going backwards one year into Erik ten Hag's project - and this time there's no transfer window to solve their problems

United actually made a good start against Brighton, looking dangerous for the opening 15 minutes. But the Seagulls scored with practically their first chance, aided by some very weak defending.

Debutant Sergio Reguilon was caught out of position and a simple pass took him out of the equation, leaving Danny Welbeck to release Simon Adingra down the right wing and drift into the area. Lisandro Martinez made a feeble effort to try and block Adingra's cross while Victor Lindelof lost track of Welbeck and the ball, allowing the former United striker to score.

The second goal from Pascal Gross, who scored twice in last season's victory, was another result of poor anticipation from United's centre-back pairing. Lindelof and Martinez were both flummoxed by Tariq Lamptey's through ball to Gross, with the Argentine not even sensing the danger until it was too late. There was also little co-operation between the midfield and the defence for Joao Pedro's goal.

Based on their performance at Old Trafford and in their previous four matches, it is hard to comprehend how Ten Hag's side registered more clean sheets than any other Premier League side last year. They have conceded 10 goals so far this season; only Wolves and Burnley have shipped more.

"We have to improve that. There are things from the team and individuals who have to step up," said Ten Hag on the defensive problems. "Sometimes you are in bad period, difficult periods, and you have to face that and deal with that. We can't blame anyone else, we have to do better and be more determined, more resilient."

When United were performing well at the end of last season it was clear they lacked a proper centre-forward. Once a top-quality striker was brought in, the theory went, the team could reach their true potential. But the idea was that the new striker would complement the team rather than carry them on his back.

Rasmus Hojlund, however, came into his full debut appearing like a knight in shining armour, tasked with rescuing United from their woeful start to the season. It was always going to be a heavy burden for a 20-year-old with only one season in Europe's top five leagues under his belt.

The Dane had an encouraging home bow, linking up well with Rashford and providing a much-needed focal point for the rest of the players to look to. But it is clear that the £72-million ($89m) man is very much a work in progress and will need time to properly dovetail with his new team-mates and acclimatise to the league. He also needs time to fully regain his fitness after arriving with a back injury which meant he could only make his first appearance for the club almost a month after joining from Atalanta.

That was evident when Ten Hag substituted him in the 64th minute for Anthony Martial, to a chorus of boos. The manager felt that it was too risky for Hojlund to play 90 minutes so soon after returning from injury. He explained: "Everyone knows he came in with a small issue, we built him up over the last three to four weeks, he is not ready for a whole game. If he gets injured because he is not capable to play 90 minutes then we are much farther away than where we want to go."

There was a great irony in Ten Hag bringing on Martial, United's most injury-prone player, to protect Hojlund, and the Frenchman offered very little in his time on the pitch, showing none of the spark or desire of the new signing.

When United fell to their shocking 4-0 defeat at Brentford in the second game of last season, Casemiro sent a text message to his agent, who had been discussing his potential move to Old Trafford. "Tell them I'll fix," he said.

Casemiro was signed for a fee rising to £70m a few days later and soon did fix United's problems, bringing world-class quality to the team and a winning mentality he had gained after so many years at Real Madrid.

Fast-forward a year, however, and Casemiro looks tired and beyond the peak of his powers. That should not be such a surprise given he is 31, but his decline sure has been dramatic and steep. Against Brighton, his passes were routinely cut out and he was not so much a wall in front of the defence but an open window, and the visitors could pour forward on the break with little resistance from the Brazilian.

Casemiro is normally the last player to leave the pitch, but he was hauled off after only 64 minutes, replaced by 20-year-old Hannibal Mejbri. He is no longer the man to fix United's problems. Instead, he could do with some mending himself.

It feels like a very long time ago now, but Sancho helped lead United's revival after their last miserable start to a season. After the twin defeats to Brighton and Brentford, Sancho scored the opening goal in the 2-1 win over Liverpool in the next game and the only strike in the 1-0 win over Leicester in their fifth match of the season.

But now, Sancho is persona-non grata after firing back at Ten Hag's criticism of his performances in training and refusing to apologise. He has been forced to train separately from the rest of his team-mates, and on Saturday was not at Old Trafford. Instead, he went to watch United's Under-18s side in action against Nottingham Forest.

Antony was another player who played his part in United's recovery from their poor start. He scored in his first three matches following his £85m ($105m) move from Ajax and became one of Ten Hag's most trusted players on the pitch.

The Brazilian's productivity then sharply declined, although he remained a first-choice pick for Ten Hag and played a big role in the manager's style of play due to his work off the ball. But Antony is now also unavailable for selection after serious allegations - which he denies - were made against him by three women in Brazil.

United really lacked a presence on the right wing against Brighton as Ten Hag's midfield diamond failed to sparkle, and the only width they got was from their full-backs Diogo Dalot and Reguilon. And it is unclear whether Antony or Sancho, who cost United a combined total of £160m ($198m), will ever play for the club again.

In Ten Hag's first campaign, United lost their first two games of the season for the first time in 30 years. In his second, they have done something unprecedented in the club's Premier League history, losing three of their opening five matches. It does not say much for Ten Hag's pre-season preparations.

The Dutch coach refused to call the spiral of results a crisis, but could not hide the fact he was concerned. "No, but we have to be very disappointed, annoyed at ourselves. We will turn this. But there is a demand on us," he said. "Definitely that is something that bothers me, but also I have to see the way we play. Finally it is about character, we have to see how strong we are, stick together."

The manager's claim that the team played well and were unfortunate to lose does not really stack up, however. Sure, they had a goal disallowed when Rashford dragged the ball out of play before squaring to Hojlund, and the England forward hit the crossbar. But, if anything, they got away lightly.

Brighton continued to come at them late in the game and Andre Onana had to make four saves in the final 10 minutes, twice denying Ansu Fati as well as Evan Ferguson and Kaoru Mitoma.

Ten Hag also referred to their last-gasp defeat to Arsenal, in which they had a goal from Alejandro Garnacho ruled out by VAR for offside and could have been awarded a penalty. He talked of "fine margins". But it is also true that United rode their luck in their only victories of the season.

Against Wolves they were fortunate to not concede a penalty when Onana clattered into two players in added time, while against Nottingham Forest they benefitted from the visitors having captain Joe Worrall sent off and winning a soft penalty when Rashford was tripped.

United should not just be concerned about their miserable start to the season and having just six points from a possible 15. Their rivals for the top four have begun the season in an impressive manner and it will take some comeback for them to catch them up.

They already trail league leaders Manchester City by nine points after their local rivals won their first five matches of the season. And Arsenal, who came second last season, have only dropped two points so far.

Liverpool and Tottenham, who finished outside the top four last campaign, have come back much stronger. Liverpool have taken 13 points and have real power of resilience, coming from behind to beat Wolves, Newcastle and Bournemouth. And Spurs, who came eighth in a shambolic 2022-23 season, look like a completely different side under Ange Postecoglou, winning their last four matches.

The season is only five weeks old but it is already beginning to feel like a long one for United. And there will be no let up. In just three days time, they visit the mighty Bayern Munich.