Aston Villa continue to threaten havoc to the established order. Just as it appeared normal service had been resumed, with Arsenal entering stoppage time on the verge of reclaiming fourth place in the Barclays Premier League from Martin O’Neill’s team, Zat Knight popped up to score the goal that keeps Arsenal on the outside looking in.

Knight was only in the team because Martin Laursen, the Villa captain, was missing a league game for the first time in two seasons, sidelined with a knee injury, and Carlos Cuéllar was out with a back complaint. The former Fulham defender planted a left-footed shot wide of Manuel Almunia in the second added minute after Gareth Barry had jostled for Ashley Young’s flick-on from Stiliyan Petrov’s low centre. The emotions unleashed around Villa Park capped a memorable evening.

O’Neill leapt along the touchline — in the opposite direction of Arsène Wenger — as if in ecstasy as he witnessed his team gain their deserved reward. The Arsenal manager left after making dark mutterings, hinting at conspiracy theories, but added: “I feel that we have the quality and a fantastic spirit because everyone gave us a loss today so we have to be happy [with the draw]. We have to keep the belief we have and we have played Villa, Manchester United, Chelsea and Liverpool and nobody has beaten us, apart from Villa, and we have improved tremendously in the last two months.”

Villa’s unbeaten run in the league started with a 2-0 victory at the Emirates Stadium seven games ago and, apart from a 15-minute spell either side of half-time, during which Denilson and Abou Diaby scored, O’Neill’s team ran this game, hitting the woodwork three times before regaining a foothold in the match when Barry converted a penalty.

Arsenal have not failed to qualify for the Champions League since 1997 but their numbers dwindled even as they warmed up. With Cesc Fàbregas headlining the list of the wounded, out for four months with a knee-ligament injury, Johan Djourou damaged his calf and was replaced by Kolo Touré. With Theo Walcott and Tomas Rosicky also injured, Arsenal’s offensive options were further undermined by the absence of Emmanuel Adebayor, serving a one-match suspension after being sent off against Liverpool on Sunday.

The game had the feeling of an early play-off for fourth place and Villa went at Arsenal from the start. Steve Sidwell was clearly as motivated as anyone, playing against his first club, and he leapt well above Alexandre Song to reach Barry’s corner and head against the bar. Villa proceeded to play with the greater conviction. They doubled up on Samir Nasri on one flank, while Emmanuel Eboué was playing strangely high up on the right wing, leaving Bacary Sagna exposed against Ashley Young, Villa’s danger man. Perhaps the hapless Eboué had misinterpreted his manager’s instruction to stick tight to Young. Luke Young, Villa’s left back, must have been flattered to receive such close attention.

In the centre of midfield, Petrov was first to every loose ball, Sidwell and Barry marauded past Denilson and Song at will. A breakthrough for

Villa appeared inevitable. Gabriel Agbonlahor turned inside Touré with ease and, when his shot was parried by Almunia, Sidwell came rushing in, only for William Gallas to block his shot.

Ashley Young crossed long for James Milner, timing his run well, to stretch and divert his shot onto a post, Almunia saving on the rebound, and then crossed for Curtis Davies to loop a shot over the goalkeeper and against the bar. Three minutes later Arsenal, galvanised by such a run of reprieves, scored. Denilson did well to tackle Nigel Reo-Coker and strode on, into the Villa penalty area, to shoot beyond Brad Friedel with a left-footed shot into the far corner. Even then, Sagna was obliged to perform an extravagant overhead kick to clear Agbonlahor’s header off the line after Villa’s leading goalscorer had outjumped Almunia.

Villa’s balloon was pricked and, four minutes after the restart, Arsenal doubled their advantage with a wonderful goal that epitomises all that is good about them. Diaby, playing in a withdrawn striker’s role, showed sublime skill to nutmeg Davies with a backheel and run round the other side of his would-be marker to lay the ball on for Eboué. He sprinted on, as Eboué ran the ball half the length of the field, to receive the return pass. After one of the longer one-twos in Arsenal’s recent history, Diaby shot home in style.

Villa may have melted away in times gone by but they are made of sterner stuff under O’Neill and, midway through the second half, hope was rekindled around Villa Park after Gallas, having allowed Agbonlahor to get goalside of him, was adjudged to have felled the England striker. Barry rammed home his penalty, even as O’Neill and Wenger squared up on the touchline.

Aston Villa 4-1-4-1: B Friedel 6 N Reo-Coker 7 C Davies 6 Z Knight 6 L Young 7 S Petrov 7 J Milner 6 S Sidwell 7 G Barry 8 A Young 6 G Agbonlahor 7 Substitutes not used B Guzan, M Harewood, N Delfouneso, M Salifou, N Shorey, C Gardner, I Osbourne.

Referee: L Mason.
Att: 42,585.

Arsenal 4-4-1-1: M Almunia 5 B Sagna 8 K Touré 5 W Gallas 6 M Silvestre 6 E Eboué 6 Denilson 7 A Song 5 S Nasri 5 A Diaby 7 R van Persie 5 Substitutes A Ramsey 6 (for Song, 44min), G Clichy (for Nasri, 82). Not used L Fabianski, C Vela, J Wilshere, N Bendtner.

Star man: Gareth Barry
Showed Arsenal exactly what they missed when they failed to capitalise on pursuing him last summer with a performance of poise and creativity. Held his nerve to score the penalty.

Window watch
Having only six substitutes sounded like a cry for help from Arsenal, even if it was caused by Johan Djourou injuring his calf in the warm-up, but Kolo Touré must be seriously out of favour if he cannot merit a starting place. A ball-winner is required, as is an alternative to Emmanuel Adebayor. For Villa, John Carew, even when he returns, cannot be relied upon to stay fit so competing for Emile Heskey as he prepares to leave Wigan Athletic, will be in Martin O’Neill’s thoughts.