Bayern Munich boss Carlo Ancelotti and captain Manuel Neuer both rued missed chances as the German champions slipped to their first defeat of the season, losing 2-0 in Hoffenheim.
Bayern never recovered from the shock of falling behind to the first of Mark Uth's two goals on 27 minutes, badly caught napping following a quickly taken throw-in from Andrej Kramaric (via a ballboy) which meant two balls were on the pitch for a brief moment.
Speaking after the match, Ancelotti blamed his side's profligacy in front of goal for the disappointing result.
"Little details decided the game, for the first goal we weren't focussed and conceded a second goal immediately in the second half. It was difficult then but we had a lot of chances.
"We controlled the game but didn't score while Hoffenheim were three times in our box and scored two goals," he said.
"In general, we played well but we weren't at 100 percent -- 95 percent wasn't enough, but that happens in football and we have to focus on the next game."
Neuer echoed his coach's sentiments, but added that Bayern
"We began the game very well and had Hoffenheim totally under control. We had a few chances and should have taken the lead," Neuer told Sky.
Commenting on the opening goal: "It all happened very quickly but basically we weren't a man down and weren't ideally positioned.
"That was our mistake and did not have anything to do with the second ball; you simply have to win the challenge. Then Uth doesn't connect perfectly with his shot and the ball goes in at the near post," Neuer said.
"I don't really want to talk about the time after. We had Hoffenheim completely under control and should have taken the lead here. That's the problem."
Last season Hoffenheim took four points from their two Bundesliga games against Bayern, with the 1-0 home win in April marking their first ever victory in 18 meetings.
Hoffenheim coach Julian Nagelsmann said: "We are delighted that we have won -- we were worse in every statistic, except for the goals.
"Luck was also on our side, but we have worked hard and proved we have a great heart.''
Bayern host Anderlecht in their opening Champions League fixture on Tuesday.
Press Association contributed to this report.