CHELSEA'S defence imploded in a game of magnificent unpredictability which will have done nothing for Andre Villas-Boas' hopes of landing the title in his first season.
The Blues, 2-1 up at the interval, seemed set fair to repair the damage done last week at QPR, but two goals in 10 minutes for Arsenal at the start of the second half turned the game on its head.
Chairman Bruce Buck, in losing this week's bid to buy Stamford Bridge, ended the meeting with a rallying cry to CPO shareholders, exhorting the Blues 'to beat up Arsenal.'
This was not quite what he had in mind.
First Andre Santos was given oceans of space on the left edge of the area to tuck home, then Theo Walcott burst past three defenders before arrowing perfectly inside Petr Cech's left hand post.
The stunned Blues thought they had salvaged a draw when Juan Mata equalised 10 minutes from time – his shot from 25 yards ballooning off Alex Song and into the net.
But the Gunners nabbed two more goals – both from the boot of Robin Van Persie, who in so doing claimed a stunning hat-trick.
The first was a particularly horrific moment for the Blues' defence as sub Florent Malouda tried to roll the ball back to John Terry from half way.
A slip by the skipper allowed Van Persie to race on unopposed and tuck home after calmly rounding a bewildered Cech.
And to rub salt in a very raw wound, Van Persie smashed home as Arsenal punished the Blues on the counter-attack.
Terry (pictured) must have believed, when he put the Blues ahead just before half time, that he was going to earn the sort of headlines that would make up for a week of unhappy publicity regarding alleged racists comments last week at QPR.
As it was, both he and his team ended up all over the place – the defence looking more like Arsenal's had been in the first half, when the Blues looked capable of netting half a dozen times, springing an offside trap which seemed to trap the Gunners rather than the home side.
The Blues failed to make the lost of getting behind the Gunners so easily early on – Fernando Torres having a close range shot deflected wide after a cross in from Ashley Cole on the left and Daniel Sturridge ought to have done better when freed on the right, but took too long to supply the supporting Torres allowing Wojciech Szczesny to smother.
But Frank Lampard gave Chelsea the lead after 14 minutes when he ghosted in unmarked to send a stooping header past the Arsenal keeper.
Lumbering centre-half Per Mertesacker was found wanting as he failed to anticipate the flight of Mata's cross from the right and was again at fault when Terry got a got on the end of a Lampard corner to put the Blues ahead again.
Rubbish they may be at defending, but no-one would accuse Arsenal of carrying no threat.
They missed two sitters just before conceding the first – Gervinho lamely pulled a shot wide when Theo Walcott outpaced Cole and sent in a low cross beyond Branislav Ivanovic, then Van Perside volleyed over from six yards after getting on the end of a nicely angled Walcott cross to the far post.
But Van Persie made amends with a goal on 36 minutes when Aaron Ramsey's clever pass allowed Gervinho to skate around the advancing Cech before slipping the ball to the hungry Dutchman.
We didn't know it then, but it was a mere appetiser from the Arsenal marksman on what turned out to be a bleak day for the Blues.
Line-up: Cech; Bosingwa, Terry, Iavanovic, Cole; Ramires (Lukaku 72), Mikel (Meireles 76), Lampard, Sturridge (Malouda 62), Mata, Torres. Subs not used: Blackman, Luiz, Romeu, Bertrand.
Attendance: 41, 801