Bayern Munich president Uli Hoeness feels the Bavarians face a tough task in successfully defending their Champions League title.
The reigning champions were paired with Manchester City, CSKA Moscow and Viktoria Plzen in Group D and Hoeness realises that it will not be easy to repeat last season's success, when they beat Borussia Dortmund 2-1 in the final at Wembley.
"Reaching the top isn't easy, but that's one thing," Hoeness told reporters.
"It's much more difficult to stay at the top for a long time, but that's the Herculean task the coach and the rest of the club have in front of us.
"But the pressure on the team is already high enough as it is, so we don't need to increase it."
The Bayern president then went on to stress that he is still confident signing Pep Guardiola as the club's new head coach was the right choice.
The Spaniard achieved his first piece of silverware with the Bavarians by beating Chelsea in the Super Cup final on penalties, and Hoeness says the team's performance in this encounter showed Guardiola's potential as coach.
He added: "I'm a 100 per cent convinced that we made the right decision in signing Pep Guardiola. I think we saw in the match against Chelsea what his team is capable of."