By FOX Sports Staff
Pep Guardiola's side looked dangerous coming into the season after racking up more than 60 goals in their pre-season matches and buffing up their squad with the likes of Mario Gotze and Thiago Alcantara.
However, they were dealt a sobering blow by Dortmund in the 4-2 Supercup defeat last Saturday ahead of the new Bundesliga season ahead of their opening fixture against Borussia Monchengaldbach this weekend.
Muller admitted that the Bavarians' performance against Dortmund was far from satisfactory, but also insisted that they will be fine going into the season.
"We were pretty disorganised after equalising and that lasted a few minutes after we conceded the two goals as well," the 23-year-old was quoted as saying on the official Bundesliga website.
"I noticed that everyone seemed to be occupying a different position. After that, we managed to regain our structure.
"When push came to shove and it mattered most, we weren't able to do the things that would have won us the match.
"It clearly means we were doing something wrong. I'll need to take another good look at the whole thing. On the positive side we didn't let up, just as we hadn't after going 1-0 behind. After being 3-1 down, we came back again. We pressed forward, got caught on the break and conceded a fourth goal.
"I can live with that, but we really needed to hold our shape better, especially when it was 1-1. I'm not pointing the finger at anyone, but it's not good enough."
He added: "Which game ever implies anything about the future? Any match can take a turn for the unexpected, however well things have been going beforehand. On top of that, we didn't play badly against Dortmund. We just weren't good enough to win the game on the night.
"Up until the Super Cup, our preparations were going really well, also in terms of results. But any team can be beaten if they don't perform at their best, ourselves included. And that applies even more when you're playing Dortmund, who are a great team as well.
"If you take last season's Champions League as the guide, they're the second-best side in Europe. So we didn't lose the Super Cup to any old team. Although that said, we'd still rather have won it!"