Arsenal showed best quality when they beat Leverkusen and they played quite well in that match.
A big win against Leverkusen sent a message to Manchester City that Arsenal really improved to face this season.
Although people think it's just a pre-season but for me the evaluation carried out by Arteta in the previous pre-season was a perfect improvement force.
Arteta understands his team's weak points and he tried to fix it and in that match he succeeded.
Next we will see how the preparations will be carried out and how they can match the Manchester City match which is no less strong.
Arsenal shown their strength and promising competitiveness for a new season. Arteta is doing necessary things before a new season, to hep Arsenal winning Premier League title after many years and trying to go far in Champions League, better than what they did last season.
Leverkusen with this defeat, can feel that a coming season won't be easy for them. It's harder to maintain a very long streak of unbeaten and it's harder to repeat it. One loss in a friendly match is not serious and terrible but it is a warning for Leverkusen that they can not live with past success. A new season is a new challenge that will be possible harder than the last season, and they will have to try a lot to achieve success with more pressure and challenge from competitors, Bayern Munich in Bundesliga and many big clubs in Champions League.