(Chelsea win 3-2 on aggregate)
Wayne Bridge's late goal stunned Arsenal and sent Chelsea into the Champions League semi-finals.
The England defender rifled home a left-foot finish on 87 minutes after being set up by Eidur Gudjohnsen to end Arsenal's unbeaten run against Chelsea.
In an enthralling match, Jose Antonio Reyes fired Arsenal into the lead from close range in first-half injury time.
But Frank Lampard drew the Blues level after a Jens Lehmann error before Bridge sealed a famous win.
Arsenal, with Thierry Henry and Reyes back in the starting line-up, were pegged back in the opening minutes.
But Lampard had the only real sight of goal, firing straight into the body of Lehmann.
45 mins: Reyes scores
51 mins: Lampard equalises
85 mins: Cole clears off line
87 mins: Bridge stuns Arsenal
And in between yellow cards for Chelsea's William Gallas and Jimmy Floyd Hasselbaink, Henry fashioned his first sight of goal and smacked a fierce right-foot shot just over.
An even better chance followed on 18 minutes after Reyes' clever through pass, but the Frenchman's shot drifted wide.
Damien Duff nearly put Chelsea ahead in sensational fashion on 20 minutes, breaking clear and cutting inside Sol Campbell before sending the ball inches wide.
Henry saw a sidefooted shot blocked and a header across goal cleared, before Robert Pires headed Ashley Cole's cross into the side netting.
Then a beautiful pass from Henry found Pires who set up Cole - but the England man's shot was blocked.
Yet just as Chelsea looked to go in at half-time all square, Reyes scored with the last kick of the half.
Lauren's probing cross was headed back across goal by Henry and although Freddie Ljungberg was unable to get a touch, the ball fell to Reyes who slotted home between Marco Ambrosio's legs from close range.
Jesper Gronkjaer replaced Scott Parker at half-time as Claudio Ranieri looked to boost Chelsea's attacking options.
The change seemed to work as Chelsea celebrated an equaliser within six minutes of the restart.
Lampard pounced after Claude Makelele's long-range strike was spilled by Lehmann.
And the England man was holding his head moments later after a beautiful 25-yard strike which curled into the side netting with Lehmann beaten.
It was little more than Chelsea deserved for their battling response to Reyes' goal, but with the scores all level, both sides became understandably cautious.
Reyes still looked lively, however, and a left-foot shot was pushed away by Ambrosio.
The Italian keeper had to be alert to tip away Toure's 40-yard effort shortly afterwards.
With 10 minutes remaining, Dennis Bergkamp came on for Henry for Arsenal, while Chelsea brought Joe Cole and Hernan Crespo for Duff and Hasselbaink.
Chelsea pressed again, and Ashley Cole made a fantastic goal-line clearance at full stretch from Gudjohnsen as the home side's defence disintegrated on 85 minutes.
But Bridge popped up two minutes later with a classy left-foot finish after a perfect one-two with Gudjohnsen to stun Arsenal.
Arsenal: Lehmann, Lauren, Campbell, Toure, Cole, Ljungberg, Edu, Vieira, Pires, Henry (Bergkamp 81), Reyes.
Subs Not Used: Stack, Keown, Wiltord, Silva, Clichy, Kanu.
Chelsea: Ambrosio, Melchiot, Terry, Gallas, Bridge, Parker (Gronkjaer 46), Lampard, Makelele, Duff (Cole 82), Gudjohnsen, Hasselbaink (Crespo 82).
Subs Not Used: Sullivan, Mutu, Geremi, Huth.
Booked: Gallas, Hasselbaink, Cole.
Referee: Markus Merk (Germany).