Bayern Munich director of football Matthias Sammer criticised his players despite watching them secure a sixth win from six Bundesliga matches against Werder Bremen.
• Werder Bremen 0-2 Bayern Munich
• Blog: Cagey coaching behind win
Bayern sealed the points with two goals in the final ten minutes, but former European Player of the Year Sammer told reporters: "Basically, it was rubbish for a really long time. During a match, the light has to be on - but today it was only flickering."
He told Bild that Bayern had to ensure they did not let compliments go to their heads, adding: "We get praise from all sides. You have to deal with that.
"We should not think: 'It's going to work out somehow.' We have to guard against that. Playing at 95% might not be enough. The match against Bremen was on the edge."
Luiz Gustavo lobbed the ball over Bremen keeper Sebastian Mielitz to open the scoring after 81 minutes, and substitute Mario Mandzukic struck two minutes later.
But the Bavarians, who lost the title despite leading the league by eight points at one stage last season, played down the significance of another victory.
"The players tried my patience a bit", coach Jupp Heynckes said, bemoaning the fact that his team were "not lively enough".
The match had seemed destined to end in a goalless draw, but the quality Bayern had on the bench made the difference.
They brought on Mandzukic, Xherdan Shaqiri and Javi Martinez during the second half, and Switzerland international Shaqiri made a huge difference, playing a key role in both goals.
Bastian Schweinsteiger pointed out the part played by Bayern's team spirit, telling Sueddeutsche Zeitung: "You feel that when we score. Does the complete bench jump up and celebrate? They do at Bayern, and that might be a difference to the national team during Euro 2012. Not everyone was celebrating there.
Bayern travel to BATE Borisov in the Champions League this week, and Toni Kroos told kicker they were targeting a return to the final after last season's dramatic defeat to Chelsea.
"The UCL title is as important as the Bundesliga title", Kroos said. "If you have been in the final once, you want to get back there again.
"We have more depth in our squad to be successful in every competition - that includes the Champions League. We will do everything we can to win the Champions League title."