Currently the best teams in La Liga are Barcelona and Real Madrid. But comparatively Barcelona team is ahead in great form. On the other hand, Benzema's place in the Real Madrid team is looking great.
Barcelona only got back to good last season because Real Madrid wasn't so consistent in winning matches, whereas previous seasons Barcelona didn't look as good as last season. So in general Barcelona are just trying to look good and that was what Barcelona managed to get last season, but for next season Barcelona still has to fight hard to be able to look even better because Real Madrid will also try to be better in La Liga and so also at UCL.
It is not as if Barcelona were only lucky to win Bundesliga last season because Real Madrid were not in good form, Barcelona were able to achieve success too because of the coach who was able to revive the team and the players in the team work very hard to make good performance. Barcelona didn't just have advantage of Real Madrid poor performance but they also work hard. During the early time in last season Real Madrid were still doing well in their games but they still couldn't make much points than Barcelona even by then , which mean Barcelona have always been ready to win the league last season.