Inter 1 Arsenal 5
Thierry Henry grabbed the first of his brace to put Arsenal ahead before Christian Vieri equalised with a deflected shot just after the half hour.
Freddie Ljungberg put The Gunners back ahead and Henry fired in a superb third goal before Edu and Robert Pires secured a famous victory in the final minutes as the Italians simply collapsed.
The breakthrough came for Arsenal on 24 minutes when Pires fed Henry who in turn looked for Ashely Cole's run into the box. Javier Zanetti stuck his foot in to deny Cole but the ball rolled out to Henry who confidently stroked the ball into the far corner past Francesco Toldo.
The Gunners looked confident after the goal, but Inter were soon back on level terms just after the half hour when Vieri found some space at the edge of the box and his low shot took a wicked deflection off Sol Campbell and looped over Jens Lehmann and into the back of the net.
The German goalkeeper then had to make a smart save from Marco Materazzi's fiercely swerving free kick as Inter applied the pressure late in the half.
Arsenal flew out of the blocks in the second half and went back in front three minutes after the restart when Henry twisted past Materazzi and squared for Ljungberg who took a touch before slotting past a floored Toldo.
Arsene Wenger took off Kanu for Gilberto Silva to protect their slender advantage, but Inter rarely threatened after the goal, and their lethargy was punished by a late flurry from The Gunners to produce a sensational result.
With five minutes left to play Henry raced clear before turning Javier Zanetti inside out and firing a stinging left-footed strike into the bottom corner giving Toldo no chance.
Three minutes later Henry stroked a great ball across the box for Ljungberg but both the Swede and Inter keeper Toldo missed the ball and Edu picked up the pieces before rolling the ball into the net to send the visiting fans into rapture.
Henry was taken off a minute from the end to receive a hero's ovation from the travelling fans, but incredibly his replacement, Jeremie Aliadiere, then forced the ball to Pires inside the six-yard box who bundled past Zanetti before stroking home to make it a staggering 5-1 scoreline.
A jubilant Arsenal are now right back into things in Group B and know that a win against Lokomotiv Moscow at Highbury in a fortnight will seal their place in the next phase.
