The League Cup may not be a priority for Arsenal but dignity obviously is. After a humiliating opening 37 minutes in which they allowed Reading to canter into a seemingly insurmountable lead, Arsène Wenger's men mounted a phenomenal fightback to turn a night of ignominy into one of glory. Amid absurdity.

The improbability of what unfolded at the Madejski was underlined by the fact that the goal which crowned Arsenal's 7‑5 victory was scored by the much-mocked Marouane Chamakh during a period of extra-time that several Arsenal players had not realised was necessary, removing their jerseys and celebrating a supposed replay after Theo Walcott had scored the second goal of his hat-trick to make it 4-4 at the end of regular time.

That was just one of the freak occurrences on a night that fluctuated unforgettably between fantasy and farce. After watching their team flounder as they shipped four goals without reply in the first period, dozens of angry Arsenal fans left the stadium in protest while others stayed to chant their disdain for the team's showing, wailing: "We want our Arsenal back." How those who left must regret that decision.

But no one will rue events more than Brian McDermott, whose Reading side were so rampant early on but who was left to wonder what ramifications this result could have for his players' confidence and the season ahead.

Arsenal, booed off at the interval, emerged buoyed. Neutral spectators, meanwhile, savoured a staggering helter-skelter match.

For a competition he considers second-rate at best, Wenger selected a second-string side, omitting all 11 of the players who had eked out a Premier League win over QPR on Saturday. In came the 17-year-old midfielder Serge Gnabry for his senior debut and the Argentinian goalkeeper Damián Martínez for his second appearance, but Arsenal still fielded plenty of presumed quality, with the likes of Walcott, Laurent Koscielny and Andrey Arshavin also starting. Wenger may have been taking the tournament lightly, but he was not planning for the failure that ensued.

After three minutes Reading's centre-back Sean Morrison headed a corner against a post. Haplessness has been a hallmark of Arsenal goalkeepers for a while now but on this occasion fortune favoured Martínez as the ball rebounded off his back and clear rather than into the net. His luck would not last, even if the 20-year-old made a solid save from Jay Tabb moments later, and Reading pierced the ramshackle defence anew.

After 12 minutes that defence was in disarray again as Noel Hunt, fending off a flimsy challenge in midfield, flipped the ball to Hal Robson-Kanu on the left. Koscielny did not appear to know where Jason Roberts was as the striker slammed the winger's cross into the net from six yards. Arsenal had started badly. And they were to get much worse.

Where Reading were vibrant and fluent, the Gunners were plain feeble. The home team cut through them again in the 18th minute before Chris Gunter fired in a low cross from the right and Koscielny shanked it into his own goal. Two minutes later Arsenal stumbled further as they lost the ball at the edge of their area and then watched as Mikele Leigertwood cantered into the box and let fly. Martínez made a spectacular attempt to palm the shot away but his technique failed him and he slapped the ball into the net instead.

Since Arsenal put up scant resistance, Reading helped themselves to a fourth goal in the 37th minute, Hunt sending a fine header in off a post after an equally fine cross from Garath McCleary. Visiting fans began filing away. Then, suddenly, Arsenal kicked back. On the stroke of half-time Walcott raced on to Arshavin's astute pass and lifted the ball over Adam Federici and into the net. That begat belief among their players, and spread doubt among Reading's

Arsenal improved immeasurably in the second half. Walcott was thriving through the middle, twice forcing fine saves from Federici. But it was his exquisite delivery from a corner that led to them cutting the deficit further in the 65th minute, when Olivier Giroud, who had just entered as a substitute, headed the delivery into the net from eight yards.

Still, it seemed that Arsenal had only managed to salvage self-respect. Then, two minutes from time, Koscielny, another major culprit in the first half, headed another corner into the net. The referee indicated a minimum of four minutes additional time but to McDermott's dismay played six, and in the last of them Walcott slammed in an equaliser after Gunter cleared Arshavin's shot off the line.

Extra-time brought no let-up in the mayhem and the match remained wildly open. Chamakh fired Arsenal in front from 20 yards before Pavel Pogrebnyak headed an equaliser in the 116th minute. A penalty shoot-out was looming but no one was ruling out a further twist; Walcott provided one as he blasted into the net from close range after Shorey scrambled an Arshavin shot off the line.

And with a fine lob Chamakh finally killed Reading off at the death. The match will live long in the memory.