This case now is simple as saying winning the trophy is easy but defending it is as hard as a nothing he has ever known before because almost the team must have studied and understood the way he plays and they would have to put twice as much efforts as they do want to maintain their position and definitely all teams wouldn't like to be beaten twice for Bayern Leverkusen to make a record on their name so all team in the bundesLiga would be out for them and what they have to offer.
Defending the trophy has always been the most challenging part of winning titles most time, it's sometimes very possible to have a one time win at a trophy but winning it for the second time and repeatedly has always been challenging to a few team as it's not been such an easy one for them because they always definitely find it even difficult thw following season as they happens to get more attention.
Except for some top elite teams who has been able to win the league title repeatedly and are now seen as a regular thing for them such that they don't really get to find it tough winning thw title buy even with such teams, they do get to a point in thw season where they are unable to win the title again so they just result to making sure they finish tops of the table probably around top four or as the runner up at the end of the season. Maintain a title usually requires a team to put in more effort than they did to win that trophy you be able to maintain it.
Just like in Italy Napoli wasn't able to even finish top four this season and rhey were thw winners of the league title last season, Leverkusen aswell will need much more than thw effort they did our in this season if they would want to maintain the bundesliga title by next season because now every team has got to know they are no longer a small team and playing against them, they will always have that in mind unlike this season they didn't have that much attention at the beginning rill at the point the season was about ending and it became obvious how good they have become.