A fine free-kick from Lukas Podolski and an emphatic finish from Gervinho were sandwiched by own goals by Jos Hooiveld and Nathaniel Clyne as Arsenal blazed into a 4-0 first-half lead. Danny Fox gave Southampton fans something to cheer right before the half-time whistle, before Gervinho and substitute Theo Walcott added extra gloss to the result for the Gunners.
With Arsenal's goal-scoring ability questioned in the early part of the campaign, the resounding score line will have been a welcome one for boss Arsene Wenger. His opposite number Nigel Adkins must be increasingly concerned by Southampton's ability to defend, though, having now conceded 13 goals in four games since their promotion to the top flight.
The scoring started as early as the 11th minute. Podolski battled through down the middle and played a neat ball inside the Southampton fullback to Kieran Gibbs whose effort was blocked at the near post by Kelvin Davis but bounced straight onto the unfortunate Hooiveld who could only watch as the ball trickled into the unguarded net.
Just past the half-hour mark, Arsenal doubled their lead. Podolski this time got himself on the score sheet with a brilliantly struck free-kick from a central position 25 yards out, although Davis may feel he should have got a hand to the effort with the ball not finding the corner of the net.
Less than five minutes later the result was put all-but beyond doubt. Mikel Arteta bided his time before splitting open the Southampton defense far too easily with a delightful chipped through ball, allowing Gervinho to burst through and drill the ball past Davis at his near post. Again the Southampton keeper will feel he should have done better.
Just a couple of minutes later the misery was piled on for Southampton as they conceded their second own goal of the contest. Gervinho played in Gibbs, again marauding to good effect down the left, and the full-back's low cross flashed off the outstretched boot of Clyne and past Davis.
Southampton did at least restore some pride by pulling a goal back right before the break. Arsenal's record of not conceding a goal this season was ended in disappointing manner as Wojciech Szczesny failed to grasp onto Jason Puncheon's lofted cross to the back post and Danny Fox was on hand to smash the ball home.
Arsenal were not finished yet, though, and continued to expose the Saints' defense in the second half. Gervinho tapped home his second goal of the game after Cazorla had produced a fine pass with the outside of his boot to substitute Aaron Ramsey, who beat Clyne before poking an effort across goal that came back off the post straight to the grateful Ivorian.
With two minutes left on the clock, Walcott came off the bench to add his name to the burgeoning list of scorers. Cazorla was again the architect as he found the forward-breaking Thomas Vermaelen, before helping the ball onto Walcott after the Belgian's shot had been well saved. The England winger made no mistake as he side-footed home the presentable opportunity to round off a memorable day for the Gunners.