Bournemouth stunned Manchester City as goals from Antoine Semenyo and Evanilson gave them their first victory over the Premier League champions.
The result ended City's 32-game unbeaten run in the competition - a record stretching back to 6 December, 2023.
It is also a second defeat in four days for Pep Guardiola's side following their midweek Carabao Cup exit at Tottenham.
The Cherries, in good form after picking up four points from their past two games against Aston Villa and Arsenal, started quickly and full of positivity.
Ederson was forced into a double save after just two minutes as he denied Semenyo and Justin Kluivert.
With the tone set, Bournemouth continued to press high and they were rewarded in the ninth minute when Milos Kerkez's cut-back from the byeline was turned in by Semenyo.
City failed to muster an attempt on target during a largely frustrating first half.
Bournemouth came out for the second period full of confidence and were close to doubling their lead in the first minute, but Ederson was sharply off his line to keep Evanilson's effort out.
Evanilson made sure with his next opportunity, though, sliding to meet Kerkez's low ball and nestling it into the bottom corner.
The hosts should have made it three moments later but Adam Smith, presented with an open goal, blazed over the bar after Marcus Tavernier's shot came back off the post.
City finally registered an attempt on target in the 80th minute, albeit a tame one, with Erling Haaland struggling to get any power on his volley.
And two minutes later, Josko Gvardiol headed beyond a despairing Mark Travers to offer hope but the Premier League champions were unable to grab an equaliser.
Deep into additional time, Haaland thought he had snatched a point but his close- range shot was saved on the line before his rebound stuck the post.
The defeat means City slip to second after Liverpool came-from-behind to beat Brighton, while Bournemouth climb up to eighth.
Cherries fully deserving of spoils
If at first you don't succeed, try, try again.
In 21 previous meetings between Bournemouth and City, the south coast outfit failed to register a single win.
Records are there to be broken, though, and Bournemouth will revel in finally getting three points against the Citizens courtesy of a well-organised and positive performance.
The only points Bournemouth had sealed against City prior to this win came during a pair of draws in 1989 and 1999.
Despite history seemingly against them, Bournemouth went toe-to-toe with one of Europe's best from the outset and full deserved their reward.
Semenyo and Kerkez were the two stars of the show but it required a team effort, especially late on as the Cherries defended stoutly to hang on for victory.
Such was the home side's dominance at times in the opening 45 minutes, their fans chanted "ole" with each completed pass.
After Semenyo's opener, which was taken really cutely as he held off Gvardiol before swivelling to slot out of Ederson's reach, Andoni Iraola's side refused to retreat into their shell and caused a headache for City by relentlessly pressing and playing with bravery.
Evanilson showed why Bournemouth parted with a club-record £40.2m in the summer to give his side breathing space and offer fans belief of a famous win.
They remained a threat on the counter during the second period with Semeyno, Tavernier, Smith and David Brooks all going close.
City's late goal led to a nervy finish but the Cherries dug in to deservedly hold out.
Man City fail to click
Pep Guardiola has made no secret of his side's lengthy injury list, claiming he had just 13 fit players after losing at Tottenham in the Carabao Cup on Wednesday.
Despite those injury issues, the Spaniard was still able to field a very strong starting eleven at Bournemouth, with the likes of Haaland, Phil Foden, Bernardo Silva, Ederson, Ilkay Gundogan and Kyle Walker all involved.
How fit all of those players are is the key question, though.
As well as losing in the Premier League for the first time since last December, it is also the first time City have lost successive games across all competitions since September 2023.
The link between midfield and attack, which is usually so seamless, was almost non-existent in the first half as City relied on crosses from wide areas to try and recover from a poor start.
Even after the restart and a likely stern talk from Guardiola at the break, City struggled to get a grip on the game.
It was not until Gvardiol, who scored his sixth goal in seven away Premier League games, forced a header into the top corner, that the visitors really started to believe.
Bournemouth undoubtedly invited pressure as they dropped deeper and City camped out on the edge of their box for the final throws.
Travers' goalline save prevented what looked a certain equaliser from Haaland and Foden spurned a great chance from the edge of the area.
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