Pep Guardiola admitted Manchester City "couldn't handle" Bournemouth as his injury-hit side lost 2-1 at the Vitality Stadium to see their unbeaten run in the Premier League ended after 32 games.
The champions were without key players, and in the absence of John Stones and Ruben Dias fielded a makeshift defence into which Bournemouth ripped with a fearless attacking display, capped by goals from Antoine Semenyo and Evanilson to beat City in the league for the first time.
Josko Gvardiol, one of a number of players to feature despite having been a doubt pre-match, scored with a late header to set up a frantic finish, but it could not preserve City's run as they slipped behind Liverpool at the top of the table.
Of particular concern will have been the ease with which Bournemouth's attack, led by the excellent Semenyo and Justin Kluivert, tormented Nathan Ake and Manuel Akanji, neither of whom were at full fitness.
"Ruben will be out until the international break," said Guardiola. "Manu and Nathan made an incredible effort to be there in a demanding game, Kyle (Walker) as well, 18 or 19 days without one training session.
"Rico (Lewis) has had a lot of minutes and was tired as well, so this is the position that we have, we try to handle the minutes. But we couldn't handle it. They were another pace today and we could not handle it."
The champions were also without Kevin De Bruyne and Jeremy Doku, fit enough only for the bench, and at times were overrun. Milos Kerkez made the opening goal, dashing round the outside of Phil Foden on the left and cutting it back centrally for Semenyo to turn Gvardiol and angle a finish wide of Ederson.
Ake in particular found the speed and direct running of the Bournemouth attack nearly impossible to contain and City were breached again midway through the second half, Kerkez racing clear and crossing to where Ake and Gvardiol had abandoned Evanilson, giving the Brazilian room to pick out the finish.
"Sometimes we have to accept that the opponents make a type of game," said Guardiola. "Sometimes you handle it and sometimes you struggle a little bit. Today it happened.
"(The players) make an incredible effort. They are players that are not in the best way and they made an incredible effort to be here.
"Manu and Nathan were not in good condition. Until the last moment I didn't know Nathan could play, he said I want to try.
"During the season sometimes, this kind of thing happens more than during other seasons. We have to handle it. People will come back and sooner or later the team will be back."
Bournemouth boss Andoni Iraola, whose team climbed to eighth having taken seven points from their last three games against City, Aston Villa and Arsenal, reflected on a fearless display from his players.
"We had to feel the pressure and it was tight at the end," he said. "I'm very pleased. One thing is to beat City but another is to play better.
"We played with no fear, tried to press when we could and defend when we had to.
"It was dangerous in the last 10 minutes. You don't enjoy that at all. There was so much pressure."