Arsène Wenger's side clinched fourth place last term after a superb end-of-season run saw them take 26 points from a possible 30.
"Every team in the league has a complicated period at some point and their level drops," he told the official Arsenal Magazine. "When the team doesn't win and doesn't get the results we want, the collective confidence drops a little. That is natural.
"Now, we've put in a spectacular run-in and you can see the difference in mentality. We have great players. I'm sure next season we'll be a better team - it's clear this squad has plenty of potential to improve."