Bayer Leverkusen is an upcoming team with low experience and also low financial stability, so you can compare them with teams like Bayern Munich, PSG, Manchester City, Barcelona, and Real Madrid. This team is far more better than Bayer Leverkusen. So it will not be a small challenge for Xavi Alonso this season because the Champions League is not that easy compared to the Europe League; moreover, even last season that they played an unbeaten season, they ended up losing the trophy against Atalanta. I know Xavi Alonso will try his best, but it will not be easy for them to face these challenges, but at least I know they will try their possible best to see they do something tangible in the season.
Since the arrival of Xabi Alonso last season, he has been quite successful in lifting the performance of this team with all the limitations that exist so that I think that there is indeed a match between the players and the tactics applied by Xabi Alonso so that they can display good performance.
For this season, it is also not much different compared to last season because Xabi Alonso did not make many changes, but regarding whether or not Leverkusen will be able to defend the title, I think it is regardless because Bayern Munich has also improved its performance and also several other top Bundesliga teams that are increasingly developing so that the competition for the title will be even fiercer.
And for the defeat experienced by Leverkusen last week, I think it will not be significant, in fact, the defeat could be a benchmark for Leverkusen to build its team much better in the future.