Ryan Christie scored just his second Premier League goal and first in 68 appearances
Bournemouth ended 10-man Arsenal's unbeaten start to the season after William Saliba was shown the first red card of his career at Vitality Stadium.
France international Saliba was dismissed inside the opening half an hour, having tripped Evanilson close to the centre circle after being put under unnecessary pressure by Leandro Trossard's poor pass.
It was a situation from which the title-chasing Gunners had already salvaged potentially crucial points against both Manchester City and Brighton, although this time the challenge was to do so for more than 60 minutes.
Their stubborn resistance was finally broken when Ryan Christie fired brilliantly in to the top corner following a clever corner routine with 20 minutes remaining, substitute Justin Kluivert flicking on Lewis Cook's low pass into the penalty area.
Kluivert then put any hope of a recovery beyond Arsenal by confidently converting his penalty nine minutes later, after club record £40m summer signing Evanilson was brought down by David Raya.
Victory ended a dismal run in this fixture for the Cherries, who had lost the last four league meetings by an aggregate score of 13-2, and moved them up to 10th in the table.
But this was a significant blow for Arsenal, who missed the opportunity to go top before leaders Liverpool host Chelsea on Sunday at 16:30 BST, after champions Manchester City visit Wolves (14:00).
'There was no need to foul him' - Shearer on Saliba red card
Bournemouth take full advantage
While Saliba's sending-off determined the pattern of the rest of the game, Bournemouth - the league’s top runners in terms of distance covered - had made an energetic start in front of their home support and refused to let Arsenal settle.
The hosts, determined to bounce back from a disappointing loss to Leicester City prior to the international break, were effective in stifling the Gunners - and Antoine Semenyo fired a warning shot over following Raya's misplaced pass.
Though still with ground to cover, Evanilson did appear to have a clear run at goal before being felled by Saliba, who accepted his fate with few complaints after referee Robert Jones upgraded the punishment from a yellow following a review.
Already high on confidence after their positive start, Bournemouth were unrelenting in their pursuit of a breakthrough to press home their numerical advantage before half-time, but a stubborn Arsenal defence survived a flurry of attempts after Raheem Sterling was sacrificed for Jakub Kiwior.
The threatening Semenyo should have done better when he blazed over shortly after the restart and it ultimately took a superb set-piece routine to put them on track for a memorable victory, sealed by Kluivert’s assured finish into the bottom corner.
Bournemouth had lost three of their past four league games - with the Leicester defeat the team's first "big mistake" according to manager Andoni Iraola, who will now hope this excellent victory can kickstart his side's season.
"We've talked about recovering the points we shouldn't have lost," Iraola said.
"It's nice to do it against Arsenal. It gets a little bit easier with the red card. It's a very valuable three points for us."
Iraola delight at 'important' win over Arsenal
Trossard at fault as Arsenal slip up
Going down to 10 men was far from unfamiliar territory for Arsenal, who since Arteta's first game in charge have been shown at least five more red cards than any other Premier League side.
But it was once again entirely avoidable. Trossard, dismissed for delaying the restart against Manchester City last month, was at fault and his awkward first-time pass back left defensive stalwart Saliba unable to recover.
Saliba’s red card will have further implications, with Arteta now left without the centre-back for next weekend’s home match against one of their main title rivals in Arne Slot’s Liverpool.
Substitute Gabriel Martinelli was thwarted at close range by Kepa Arrizabalaga less than two minutes before Christie’s opener in a crucial second-half turning point, which led to the abrupt end of Arsenal's 16-game unbeaten run in all competitions.
Here the visitors sorely missed the attacking influence of Bukayo Saka - Arteta choosing not to risk the winger after the injury he sustained on international duty with England - adding to the longer-term absence of captain Martin Odegaard.
Arteta will hope for a swift return of his key players for the challenging battles ahead, with Liverpool, Newcastle and Chelsea to come in the league in a period which is sure to test their title credentials.
"It's very difficult to win in the Premier League with 10 men for 60-70 minutes, it's just an accident waiting to happen," said Arteta.
"We have had to go through it in three games and that cost us the game."
Red card 'cost us the game' - Arteta
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