A (partial) new owner, new signings, a new mood, but for Manchester United it was a very familiar story. João Pedro got the winner in the fifth minute of injury time and, while United will lament a farcical second-half offside that denied them the lead, Brighton had looked the likelier to score for all but about 10 minutes of the second half.

For United this was another performance that was probably better than equivalent games last season, but still far from good enough. The gains of the Dave Brailsford era have, so far, been a little too marginal.

“I saw some good parts,” said Erik ten Hag. “Counterattacking, buildup and in possession, how we defend …But in the second half we should have kept more control in the game. In both boxes we have to be more clinical and more aggressive. Both goals were very soft.”

Brighton’s winner came after a sustained spell of pressure, Simon Adingra dinking a ball to the back post where three Brighton players were lined up waiting to apply the coup de grace.

For all that United might have drawn quiet encouragement from the way they pressed, from their sense of shape and structure, they suffer a want of conviction, a lack of ruthlessness. Fundamentally, there is a bewildering incapacity to do the simple things right. Where were the markers? Why, when they had eight players in the penalty area, was half the six-yard box vacant in the 95th minute? And why had Adingra been allowed to check back on to his stronger right foot?

The first goal had been similar, everybody standing off João Pedro, granting him time to bend a dangerous ball across the six-yard box. Although nobody got a touch, the ball came to Kaoru Mitoma as he stole behind Noussair Mazraoui. Danny Welbeck then turned in his low cross.

Welbeck was the future of United once, a local lad and a fan with a knack for goals. He left in 2014, two years before Marcus Rashford, another local lad and a fan with a knack for goals, made his debut. The 26-year-old increasingly looks a player whose potential will not be realised at Old Trafford.

It was Rashford whose pass to Bruno Fernandes was intercepted by Billy Gilmour in the buildup to the Brighton opener. He had a miserable end to last season and his form has not improved. There is an obvious sense of a player doubting himself and out of sorts with the world. An attempt to take a free-kick quickly just before half-time that pointlessly gave the ball away was typical; his sense of urgency has curdled into a tendency to rush things. Again and again he made runs slightly too early and so moved offside. He looks frustrated.

Injury forced the withdrawal of Mason Mount at half-time, and the introduction of Joshua Zirkzee. United promptly looked more open and more likely to score, and after James Milner had one cleared off the line and Welbeck headed against the bar Amad Diallo levelled.

Zirkzee is surely the player of greatest circumference seen in the Premier League since Tom Huddlestone (who, curiously, left United’s coaching staff in the summer to take up a role with England Under-21s; maybe Carrington wasn’t big enough for the both of them). He might perhaps have benefited from being a little less big when, unable to stop his slide like an aquaplaning juggernaut, he inadvertently kneed Alejandro Garnacho’s goalbound shot over the line, causing it to be ruled out for offside.

“It was a wake-up moment for us,” said Fabian Hürzeler. “We’d lost a little momentum and the game was too open. But how we played the last 10-15 minutes was amazing. What I want is that we show the attitude of never giving up, try to be the best prepared team, try to outwork the opponent. I try not to be euphoric because that distracts you from the processes.”

Comedy like United’s disallowed goal deserved a punchline, and João Pedro delivered it. Brighton look like being hugely entertaining this season; United, for very different reasons, may also be.