The Catalan giants lost the first leg 4-0 at the Allianz Arena in Munich last week and the Germany international admits that they can overhaul that deficit at Camp Nou on Wednesday.
"Barcelona can turn the tie around – they are capable of it," he told UEFA.com. "Barcelona have been wounded so that makes them dangerous. The first leg has opened the door but we haven't crossed the threshold yet.
"It'll be a difficult match as few teams have stood up to Barcelona at the Camp Nou. We have to be even more focused than in the first leg. It'll be tough because Barcelona are capable of great things. The pitch is slightly larger so it might be tough for those who haven't played here before. The Barcelona fans will get behind their team, but we have to stay focused on our objective and forget what is around us.
"It's always an honour to represent this club and these nights are always special. We have to be ourselves and we want to represent the club because we're proud of it. It's an honour to play this match. We are in tip-top form and it is great to be able to play at the Camp Nou, really motivating."
Bayern reached the Champions League final last season but lost to Chelsea on penalties.