Mikel Arteta's side were on course to keep pace with leaders Liverpool after goals from Gabriel Martinelli and Kai Havertz put them in control at the Emirates Stadium.

But the Gunners collapsed midway through the second half as Youri Tielemans' first league goal this season handed Villa a lifeline before Ollie Watkins bagged the equaliser.

Boyhood Arsenal fan Watkins was about to be replaced by Jhon Duran before his 10th league goal this season put a huge dent in the north Londoners' hopes of catching Liverpool.

There was an agonising finale for Arsenal as Mikel Merino's late winner was disallowed for handball by Havertz.

Second-placed Arsenal are now six points behind Liverpool as their bid for a first title since 2004 continues to splutter.

Darwin's Nunez's stoppage-time double for Liverpool sealed a 2-0 win at Brentford just half an hour before Arsenal kicked off, with groans audible from the stands as the result reached fans at the Emirates.

And with Liverpool holding a game in hand on Arsenal, Arne Slot's men are firmly in control of the title race.

Arsenal's 2-1 win against north London rivals Tottenham on Wednesday had ended a damaging run of three games without a win in all competitions.

That frustrating streak included the FA Cup exit against 10-man Manchester United and a League Cup semi-final first leg loss to Newcastle.

There was a pre-match blow for Arsenal as French defender William Saliba was ruled out with a "minor issue" and Villa eventually exploited his absence.

Villa had ruined Arsenal's title bid last term, beating them twice in the league including a crucial 2-0 victory in north London in April.

Emery haunts Arsenal 

Despite partially avenging those losses with a win at Villa earlier this season, Arsenal found themselves frustrated by their former boss Unai Emery again.

Despite being penned deep inside their own half for most of the opening 10 minutes, Villa should have taken the lead when Ian Maatsen's fierce strike from 12 yards forced a fine save from David Raya.

Arsenal's pressure was rewarded in the 35th minute as Leandro Trossard whipped a cross into the six-yard box and Martinelli got in front of Maatsen to stab past Martinez, whose save couldn't quite stop the ball crossing the line before he clawed it out.

Havertz headed over from Martin Odegaard's free-kick, but the much-maligned German finally ended his recent struggles to double Arsenal's lead in the 55th minute.

Trossard cleverly shifted the ball away from Villa defender Matty Cash and whipped a low cross towards Havertz, whose close-range finish eluded Martinez's weak attempted save.

The 25-year-old's first goal in four games took him to 13 in 29 matches in all competitions this season, but he would still finish as the villain.

Tielemans led Villa's instant fightback, getting in front of Merino to meet Lucas Digne's cross with a diving header from six yards in the 60th minute.

Arsenal were rocking and Tielemans nearly equalised 90 seconds later with a snap-shot that smacked back off the post.

Martinelli volleyed wide from Gabriel's lofted pass, foreshadowing the pain to come for Arsenal in the 68th minute.

Cash's cross arrowed into the Arsenal area and Havertz couldn't head clear, giving Watkins the chance to guide a clinical finish into the roof of the net from close-range.

Merino briefly thought he had spared Arsenal's blushes but his strike from the edge of the area was disallowed for the clear contact with Havertz's arm.

In a thrilling finale, Merino hit the post before Martinez made a superb save to repel Trossard's effort from the rebound as Arteta held his head in disbelief.