Midfielder Thomas Mueller has admitted Bayern Munich were punished for their complacency in their shock 3-2 defeat by Manchester City, who proved the Champions League winners are not unbeatable.
Bayern suffered their first defeat under Pep Guardiola since losing the German Super Cup final to Borussia Dortmund in July as their record 10-match winning streak in Europe was brought to an abrupt halt.
Having raced into a two-goal lead after 11 minutes at Munich's Allianz Arena with goals by Mueller and Mario Goetze, Bayern allowed City to fight back on Tuesday in their final group game.
David Silva and stand-in captain Aleksandar Kolarov both scored before winger James Milner capped an outstanding display to hit the winner with a superb curling shot to complete the miraculous fight-back.
"The human-factor came out in us and we played too carelessly," admitted Mueller, as Bayern progressed to the last 16 as Group D winners despite the defeat after winning five of their six games.
"Everyone ran too little after we went 2-0 up.
"It's not like we missed chance after chance, but we weren't able to compensate for the two goals they scored.
"After such a strong start, we had imagined the game would have gone differently.
"We have a lot of self-confidence at the moment and after we went 2-0 up, you thought 'what could possibly go wrong now?'
"We lost 3-2, so that was the best of our possible worst case scenarios."
City would have finished as group winners with a 4-2 victory and Mueller said keeping hold of possession had been his priority in the dying minutes to avoid conceding a crucial fourth goal.
"That's why I dribbled towards the corner flag in the 87th minute to keep the ball," said the Germany star.
"But I was left wondering about the rest of the side when our entire team were in the Manchester penalty area two minutes later, so I don't know if the others were aware.
"We never go into a game expecting to lose 3-2, especially not at home.
"Sure, Manchester are good for a goal or two, that's no secret.
"But we let things slip after a good start. The absolute will to win was missing."
Bayern have had their Champions League record run ended, but they can add to their 40-match unbeaten streak in the Bundesliga on Saturday when they host Hamburg, who they also face in February's German Cup quarter-finals.