I have been thinking about the drop in Haaland's form recently. First of all it is totally normal for any player of course. I have been just thinking about whether there could be a special reason affecting it as well. De Bruyne's absence came to my mind after that. The reason why is that there was a great relationship between these two players. 
De Bruyne was sending a lot of balls to Haaland to make him more active and effective in the attacking line. You know how great De Bruyne can pass the balls to his teammates. He is like a magician. I hope that Haaland can reach his usual level sooner or later. I'm still contented with his goal effort so far of course. But I would like to see him doing good during the full season as well.
De Bruyne was sending a lot of balls to Haaland to make him more active and effective in the attacking line. You know how great De Bruyne can pass the balls to his teammates. He is like a magician. I hope that Haaland can reach his usual level sooner or later. I'm still contented with his goal effort so far of course. But I would like to see him doing good during the full season as well.
And it was yet another goalless night for Manchester Citys number 9. He still wasn't with a goal as they went on to lose to Spain with the only goal coming from Gavi.
Kevin De Brunye had his effects too but not just him. Jack Grealish played important roles for Erling Haaland last season, dribbling, creating chances for Erling Haaland alongside the others.
He found it worrying as he wasn't scoring but few games later, you'll see how he handles himself, supporting and assisting,that made him a better player last season.
Asides him, Jaoa Cancelo and IIkay Gundogan, Mahrez also shouldn't be forgotten. All these players were core spines to Pep Josep Guardiola's team.