The Gunners controlled proceedings after a tardy start and managed to hit the front a few minutes before half-time through Alex Song.
Then the floodgates opened after the break with goals in quick succession from Cesc Fabregas and Theo Walcott before Chelsea defender Branislav Ivanovic pulled one back just before the hour-mark to consign the reigning champions to their third loss in six matches – the other three being draws.
The Gunners were attacking with frequency after the opening 10 minutes and finally managed to break through late in the first term when Song played in Jack Wilshere who knocked it back into the path of the defensive midfielder who received some good fortune as the ball bobbled into his path. GOAL The Cameroonian finished from just outside the six-yard box for his fourth of the season.
GOAL The Gunners’ second goal came six minutes into the second half when Chelsea’s Michael Essien knocked the ball back into the path of Theo Walcott who pushed it toward Fabregas who had time and space to easily shoot past Petr Cech.
GOAL And all of a sudden it was 3-0 when Fabregas turned provider by repaying Walcott with a neat through ball which the promising winger finished with aplomb across Cech in the 53rd minute.
GOAL Chelsea got themselves back into the contest in the 57th minute when Didier Drogba’s free-kick was nodded home by Ivanovic but the home side had done enough.
The win was Arsenal’s first over their London rivals since November 2008 and allowed them to go second, two points behind league leaders Manchester United, as the Blues remained fourth, six points off the Red Devils.
Lukasz Fabianski (gk), Laurent Koscielny, Johan Djourou, Gael Clichy, Bacary Sagna, Alex Song, Jack Wilshere, Cesc Fabregas (Rosicky 88’), Samir Nasri, Theo Walcott (Diaby 73’), Robin van Persie (Chamakh 76’)
Subs - Wojciech Szczesny (gk), Abou Diaby (73’), Marouane Chamakh (76’), Tomas Rolsicky (88’)
Petr Cech (gk), John Terry, Branislav Ivanovic, Ashley Cole, Paulo Ferreira (Bosingwa 61’), John Obi Mikel (Ramires 46’), Frank Lampard, Michael Essien, Florent Malouda (Kakuta 56’), Didier Drogba, Salomon Kalou