Regarding the game between Atalanta and Arsenal, I don't know why but Arsenal had totally disappointing performance in this match and they easily lost a point against Atalanta while this team was not strong like Arsenal and they didn't have superstar players like this team at all. It seems Arteta is even more experienced enough and he still can't have a good performance in the bigger tournaments like the Champions League with Arsenal.
Also, Arteta should thank David Raya for his good performance because he saved a penalty kick for his team otherwise they could lose this game against Atalanta.
If we look at the squads of the two teams that played in the match, we can say that actually the two teams are not in good condition, considering that many of their main players are injured, if we compare in terms of team quality, of course, actually Arsenal is still better than Atlanta, but indeed Arsenal's game in the match does not show a team that has attractive characteristics and is also impressive in attacking, Even in my opinion after the game against Porto last season it was clear that the game against Atlanta was the second worst game I have seen from Arsenal in the Champions League so far.
I totally disagree with you, if you had watched that game very well you would have seen that Atalanta where the better side against Arsenal, don't even go to say that Atalanta is not strong as Arsenal, Atalanta played without any sign of weakness in that game, you might want to rate them not being on the same standard with Arsenal but every club that has qualified for the champions League came as a champion especially Atalanta that won the Europa League. I still blame that young man that went to play the penalty for Atalanta as he would have allowed ademola lookman to take the penalty kick, maybe by now you would have understood that Atlanta came prepared if they had won that game.
I don't think Arsenal failure to get full points in that match is just because Atlanta is a good team after they won the Europa League last season, because I think Arsenal mentality is actually very weak when they play in the Champions League so far, especially so far Arsenal has a bad record when facing a Serie A teams in Italy, but Arsenal should be grateful to Raya who is able to perform consistently at this time in guarding the Arsenal goal and we also cannot blame Retegui for failing to take a penalty in the match, because after all, a player has a burden when taking a penalty kick, especially if the penalty is a penalty that determines the a team victory.