Bayern Munich coach Pep Guardiola believes the absence of Manchester United from this season's Champions League serves as a warning to all elite clubs, reports BBC Sport. United are sitting out the competition for the first time since 1995 after finishing seventh in the Premier League last season.
"It is a good lesson for the big clubs if we think we are unbeatable, that we are so strong," Guardiola said ahead of his side's Champions League tie with Manchester City on Wednesday.
"Every year we need to make the good things or maybe next season you could be out. That is why football is magnificent. Every single week you have to be ready."
