As long as Xabi keeps playing with the system that already worked so far, he is going to get good results and nothing will change much. I know that it may not look like that with just one loss but that's just one loss, in fact it's their first loss in nearly forty games of Bundesliga, we should be more forgiving against that, plus it wasn't like some relegation level team, it was Leipzig and shit happens, we shouldn't really make a comment on what's going to happen with just one game.
There is no doubt, Alonso is a good coach, he set a record in the Bundesliga that will be hard to brake, he is also very young which means his coaching career can still go further because I am very sure if Anceloti will be leaving Madrid, they will contact Alonso to offer him the job.
Remember, Leverkusen performance was not as it used to be towards the last season, they hardly win matches because their pattern of football was noticed towards the end of the season which is why they find it hard to even get a draw at the end, but they are very lucky and complete the last season’s Bundesliga matches undefeated. But it might not be possible this season.
I am not saying Leverkusen will win the league title again, maybe they will or maybe they won't we can't know that, but if they win it then we can say one game didn't matter that much, and if they lose it, it won't be because of just one single game, they would have to lose even more.
They look like a team that can win League this season. I am not understanding them this time, but their lack signing during the transfer summer will deeply affect the team because they don’t have squad depth and the competitions are much because they are playing in the Champions League again this season.