Rarely have the two contrasting sides of Arsenal under Arsene Wenger been more evident than last night.
For an hour, his team were fluent, confident, entertaining and clinical in taking a 3-0 lead that had seemingly guaranteed their place in the knockout phase of the Champions League for a 15th straight season.
Alexis Sanchez had again justified comparison with Luis Suarez, both by scoring what was his 11th goal in 13 games with a brilliant volley and having a hand in Arsenal's two other goals with his tireless running off the ball.
But, then, quite without warning, Wenger's team seemed almost to suffer a collective nervous breakdown as Anderlecht exposed familiar defensive weaknesses by scoring three times in a dramatic finale.
It was a comeback to top even Arsenal's fortuitous late win over Anderlecht two weeks ago and which evoked memories of the 4-4 draw against Newcastle when the team had once led 4-0.
It also means Arsenal still have work to do in their final group games, against Borussia Dortmund and then in Istanbul when they face Galatasaray.
Wenger had spoken before the match of the need for Aaron Ramsey to recover his form of last season by not obsessing about scoring goals but, equally important, was the chance to again pair him in central midfield with Arteta.
That was Arsenal's best combination last season and, with Mathieu Flamini dropping to the bench to make way for Ramsey, Wenger's team had an edge to their attacking play that has been only rarely evident this season.
With Alex Oxlade-Chamberlain and Santi Cazorla again providing the width and Sanchez continuing to thrive in the roaming striker's role he has played of late, Arsenal carried an immediate threat with every attack.
Oxlade-Chamberlain's pace down the right provoked the first chance, with his cross falling to Ramsey, who was denied only by a goal-saving challenge from Chancel Mbemba.
Calum Chambers was also overlapping with regularity down the right and, from his cross, Sanchez brilliantly brought the ball under control and smashed the outside of the post with his shot.
Wenger had pointedly noted before the game that every opponent now simply attempts to exploit Arsenal's possession-based style with rapid counter-attacks and, as was the case in Brussels two weeks ago, this was certainly Anderlecht's strategy.
Once again, being aware of the threat and knowing how to nullify were two completely different issues for Wenger's team.
Danny Welbeck sloppy loss of possession allowed Dennis Praet to sprinting into space and exchange passes with Gohi Bi Cyriac before having his shot deflected narrowly wide.
From another counter, Cyriac created a second clear chance for Anderlecht, with Sacha Kljestan then forcing an excellent low save from Wojciech Szczesny.
Arsenal were riding their luck but creating enough good chances to continue taking risks and were rewarded for their adventure in the 25th minute.
Ramsey passed to Sanchez who, in turn, released Welbeck into the Anderlecht penalty area.
He was running away from goal but had got in front of Mbemba who rashly attempted to recover his position but only succeeded in bundling the Arsenal striker to the floor.
Referee Clement Tupin signalled for the penalty and Arteta coolly waited for goalkeeper Silvio Proto to commit himself before chipping a 'Panenka' down the middle of the goal.
It was the 500th goal to be scored at the Emirates. It also spurred Arsenal and, four minutes later, Sanchez collected the ball deep inside his half and sprinted into the Anderlecht defence.
Anthony Vanden Borre was unable to match the Chile striker for pace and, although subsequent contact was minimal, Sanchez went down for a free-kick on the edge of the penalty area.
He got up, shot his first effort straight into Cyriac but then, as the ball ballooned back into his path, smashed a follow-up volley straight through the wall and inside Proto's near post.
Arsenal might then even have gone 3-0 clear by half-time when Ramsey released Welbeck but the former Manchester United striker was unable to lift the ball past Proto.
Arsenal retained their momentum at the start of the second half and further extended their lead when Sanchez pounced on a mistake by Kljestan and released Oxlade-Chamberlain.
The former Southampton winger easily then outpaced Vanden Borre, a former Portsmouth full-back, to go one-on-one with Proto and guide his finish into the far corner.
For all their attacking quality, Arsenal's vulnerabilities also did not evaporate.
Chambers was too passive in allowing Andy Kawaya to get himself into position to cross and, while Vanden Borre was clearly offside, he went unchallenged to tap in what had looked like it should be a consolation.
Yet still Anderlecht threatened and were themselves awarded a disputed penalty when Monreal clumsily tangled with Aleksandr Mirovic. Vanden Borre duly side-footed the penalty past Szczesny.
Arsenal's nerves were further frayed by the loss of captain Arteta to a hamstring injury and the equaliser had certainly been coming when, in the 90th minute, Cyriac got in front of Per Mertesacker to head Najar's cross past Szczesny. (© Daily Telegraph, London)