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.
It’s not something new that since Xabi Alonso came to the management of Bayer Leverkusen, everything has changed for good. He maintained an unbeaten record through out a season, a very good impact on Bayer Leverkusen and also on Xabi Alonso's career, but one thing is that this season will be a difficult season for Bayer Leverkusen because Dortmund and Bayern Munich are also ready for this title race, and with the way these two teams performances are increasing, it makes me believe that Bayer Leverkusen will face a tough time this season; even if they get the title, it will be easy as it was last season.
I know that Xabi did his best to avoid too many changes that will affect the performance of the players so he will be able to maintain the same thing as last season, but since this season started, I have not seen any result that can convince that Bayer Leverkusen will be the same thing as last season, although the season just started, but Bayern Munich are back and their performance is good.