Of course there are still some question marks over United – they clearly were not perfect because they lost.
They may need a new central midfielder to replace Manuel Ugarte or Casemiro, because I know not everyone thinks they are the ideal fit alongside Bruno Fernandes, who might need someone more powerful to do a bit more running for him.
There are doubts over their goalkeeper situation too, which cost them again here with Altay Bayindir’s mistake for Riccardo Calafiori’s winner.
It is frustrating to lose to a goal like that anyway, but especially because it is something that has happened to them before.
However, while there was disappointment on the day, this was still a game that gives United plenty to build on.
Of course you always want results, but you also want to see some progress – especially at this extremely early stage of the season – and United’s display showed plenty of that.
Right now progress means the team getting better and more used to the manager’s system, with the players becoming comfortable in their relationships on the pitch, and the new signings bedding in.
It is also about them putting their struggles of last season behind them, and playing with some confidence and belief.
All of that happened against Arsenal.
Although they lost, they played like they thought they could win, and every team who plays against them now is going to be wary.
Danny Murphy was speaking to BBC Sport’s Chris Bevan.