Even though Haaland missed a couple of defent chances and Villa's goal was a deflection, they were by far the better team and fully deserved to win.
We didn't look remotely like scoring a late equalizer, did we even create a single chance in the second half? Compare that to Arsenal and Liverpool who always look like scoring late goals.
I'm not that surprised we got outplayed when our midfield consisted of a central defender coming back from a long absence, a right-back who may or may not go on to be a good player and a striker. That's a massive drop off from the midfield that lead us to the treble (Rodri, Gundogan, De Bruyne) and it inevitably showed.
I think we also have to give credit to Villa. They have a top manager and have recruited very well. As Pep often says when he's criticised for not winning every single game, "the other teams are good too."