Mikel Arteta's side fell behind to Matty Cash's first half goal at Villa Park before Leandro Trossard came off the bench to equalise for Arsenal after the interval.

A pulsating clash featured squandered chances for both teams before Argentine winger Buendia capitalised on sloppy Arsenal defending to bag the winner with virtually the last kick of the game.

It was Arsenal's first loss in all competitions since they were beaten for the only other time this season in a 1-0 loss at Liverpool on August 31.

Villa have been a thorn in Arsenal's side several times in recent seasons, taking points from them at crucial moments in the title race.

This was another frustrating encounter with Villa's former Arsenal manager Unai Emery, whose team have emerged as unexpected title contenders following a flurry of seven successive victories in all competitions.

Arsenal are just three points above second-placed Villa, with third-placed Manchester City able to close the gap on the leaders to two points if they beat Sunderland at the Etihad Stadium later on Saturday.

Emery had dismissed any talk of his side being in the title race this week, calling Arsenal the strongest team in Europe.

But this was a significant statement of intent from Villa, who went toe to toe with Arsenal and delivered a painful blow to their title charge.

It was an ideal time to play the north Londoners, who are dealing with a crisis at centre-back with William Saliba, Gabriel and Cristhian Mosquera all sidelined.

Jurrien Timber moved from right-back to centre-back to fill the void alongside Piero Hincapie, but Arsenal never looked completely comfortable.

Arteta has said that Arsenal are "prepared" to do business in the January transfer window if there is an option to "improve" the squad.

Defensive reinforcements and additional attacking options may be needed if Arteta is to lead injury-prone Arsenal to their first English title since 2004.

- Frantic finale -

David Raya almost gifted Villa the perfect start with a nervous, miscued clearance that forced Arsenal's keeper to scramble back to save.

Ollie Watkins grew up as an Arsenal fan and the Villa striker nearly made his boyhood favourites suffer in the opening minutes.

Youri Tielemans' flick gave Watkins a clear sight of goal, but Raya made a superb save to repel his strike.

Emiliano Martinez had to save from Bukayo Saka's curler moments later before Eberechi Eze's close-range finish was ruled out for offside.

Cash scored Villa's winner against Manchester City earlier this season and he tormented another title contender in the 36th minute.

Ian Maatsen's cross was flicked onto Cash at the far post and the defender slammed a fierce finish past Raya.

With Arsenal having won only one of their previous 15 Premier League games when trailing at half-time, Arteta responded by sending on Trossard and Viktor Gyokeres.

Belgian winger Trossard made an immediate impact, forcing a save from Martinez and then volleying inches wide from 10 yards.

Arsenal had the momentum and they drew level thanks to Trossard in the 52nd minute.

Martin Odegaard raced towards the Villa area and slipped in Saka, whose low cross reached Trossard for a clinical finish at the far post.

Trossard's sixth goal this season took him to 50 in his Premier League career.

Arteta's men were almost caught on the counter when Watkins broke free for a shot that Raya saved at full stretch.

Odegaard's long-range rocket was brilliantly tipped over by Martinez, while Villa's Donyell Malen fired just wide in a frantic finale.

Arsenal were seconds away from escaping with a draw but Buendia netted with a ferocious blast into the roof of the net from 12 yards after the Gunners made a hash of clearing.