We’ll see on Matchday 1 how prepared they really are when Arsenal comes to Old Trafford with their new line-up — Gyökeres, Zubimendi, Madueke, and others. I don’t think Man Utd has prepared themselves properly for yet another Premier League season.
The first game will be a big test for both teams because it'll be the first Premier League game of the season and a chance for the supporters of each team to evaluate how prepared their teams are for the new season. For Arsenal not winning the game will mean that they're not prepared for the season and for Manchester United they will come under crazy criticism if they lose by a huge margin to Arsenal because the supporters of the club would not like to finish at the same position where they finished last season.
I predict Arsenal to win that game, they look to have a better structure than Manchester United currently, but I will still not underestimate Amorim and his tactics.