William Saliba was sent off as Bournemouth dealt Arsenal a first defeat in the Premier League this season.
The defender was dismissed for hauling down striker Evanilson near the halfway line, denying him a clear run on goal as for the third time this season the visitors finished a league game with 10 men.
Andoni Iraola's side saw a chance to inflict Arsenal's first loss of the season and took it most clinically, taking the lead 20 minutes from time when substitute Ryan Christie hit an unstoppable effort into the top corner just as Arsenal appeared to have come through unscathed from the worst of Bournemouth's pressure.
Arsenal pushed on and inevitably left gaps. Evanilson took advantage when he got in behind and was felled by goalkeeper David Raya, handing Justin Kluivert the job of capping a fine victory from the penalty spot.
An uneventful opening 20 minutes saw the Gunners limited creatively by Bournemouth's disciplined high press, the closest either side came to a goal when Raya gifted the ball with a dreadful pass only for Antoine Semenyo to thrash at the chance.
The shape of the game shifted with the sending off in the 30th minute. Evanilson still had the whole of the Arsenal half to traverse in pursuit of a looped ball over the top but crucially had manoeuvred goal side of Saliba and threatened to race clear.
Saliba was the last man - there was little chance of Ben White making up the distance to cover from right-back - and clearly dragged Evanilson to the ground, though it took a pitch-side review to convert Robert Jones' initial yellow card to a red.
Arsenal had gone down to 10 against Brighton and Manchester City this season and each time set up defensively to preserve a result, but they might have defied their predicament and gone ahead had Mikel Merino not dragged wide from Marcos Senesi's poor defensive header.
Arteta sacrificed Raheem Sterling for defensive reinforcement in the shape of Jakub Kiwior, and thereafter Bournemouth penned Arenal back.
Raya gifted them a chance when he fumbled Semenyo's low cross then immediately saved a certain goal, springing up in a blur to smother Marcus Tavernier's rebound.
Semenyo blew a golden opportunity to make hay on Bournemouth's advantage at the start of the second half, ballooning over after Milos Kerkez picked him out in space at the far post.
Gabriel Martinelli was sent on in attack, an affirmation of Arteta's belief his side could nick it.
Indeed they might have but for Kepa Arrizabalaga's fine save with his legs from the Brazilian after initially giving the ball away with a casual pass.
It capped Arsenal's best spell since the red card but soon they were rocked by Christie's rocket, blasted in first time from a corner past a static Raya as Kluivert's clever flick fooled the visitors' defence.
Not long after, Arsenal's fate was sealed. Kiwior carelessly allowed Evanilson to nip in over his shoulder, Raya raced out to repair the damage but in his haste toppled the striker. Kluivert sent the goalkeeper the wrong way from the spot for 2-0.
