Phil McNulty
Andres Iniesta's spectacular strike deep into stoppage time wrecked Chelsea's dreams of a second successive Champions League final against Manchester United amid chaotic scenes at Stamford Bridge.
Chelsea looked to have kept Barcelona at bay again and sealed an all-Premier League clash in Rome on a night of nerve-jangling tension after Michael Essien's 20-yard blockbuster in the ninth minute.
But with Guus Hiddink's side hanging on desperately - and fuelled by a sense of injustice after Norwegian referee Tom Henning Ovrebo rejected a succession of penalty appeals - Iniesta beat Petr Cech from the edge of the area to send Barcelona into the final.
It was a heartbreaking moment for Chelsea and one that was too much for Didier Drogba, on the sidelines after being substituted with an injury, to bear.
There had already been angry scenes in the technical area after Barcelona's leveller, with Hiddink appearing to be buffeted on the touchline, but there was still no excuse for the loss of control from Drogba, whose lack of discipline saw him sent off in last season's Champions League defeat in Moscow.
He showed few signs of his earlier injury as he marched on to the field clad in flip-flops to subject referee Ovrebo to a prolonged verbal tirade, for which he rightly received a yellow card. Drogba refused to be deterred by this punishment and continued to purse the official while being held back.
Ovrebo eventually made his way down the tunnel with Drogba still trailing in his wake. It was a shameful conclusion to a dramatic encounter and once again raises serious questions about Drogba's temperament.
Frustrated he may have been, but to act in such a manner only exacerbated an already angry mood inside Stamford Bridge.
Chelsea looked on their way to the final, and potential redemption after last year's defeat, after a superb defensive display that restricted Barcelona all night until Iniesta's deadly strike.
Drogba wasted a perfect opportunity to secure a second goal for Chelsea early in the second half, only to strike his finish against Barcelona keeper Victor Valdes.
But Chelsea's real bone of contention came from those penalty appeals especially a first-half collision between Drogba and Eric Abidal, then a clear handball by Gerard Pique after the break.
Barcelona now face United in the final - but it was victory at a price with Dani Alves ruled out of the final after a booking and Abidal also missing after he was unluckily sent off after referee Ovrebo adjudged him to have fouled Nicolas Anelka in the second half.
Chelsea must now gather their forces for the end of the Premier League campaign and the FA Cup Final against Everton - but the glittering prize of the Champions League has eluded them once more.
Barcelona's attempt to secure a crucial away goal suffered a blow before kick-off when Thierry Henry was ruled out with a knee injury - while Chelsea included both Drogba and Anelka in their line-up.
The Catalan giants posed the first threat when Xavi's effort took two deflections before Chelsea's Jose Bosingwa cleared from almost on the goal-line.
And Chelsea took advantage of that escape to make the crucial breakthrough after only nine minutes, thanks to a 25-yard blockbuster from Essien.
Lampard's pass was half-cleared, and even though there seemed little danger Essien met the loose ball with a thunderous left-volley that left Barcelona keeper Valdes stranded as it ripped high past him and into the net off the bar.
Barcelona's response was predictably measured as they refused to stray from their trademark passing approach, but it failed to reap any rewards as Chelsea keeper Cech remained well protected by his defenders.
Indeed, it was Chelsea who had the better chances despite having less of the possession, with Valdes just beating Drogba to Frank Lampard's long ball before diverting away the striker's angled free-kick with his knees.
John Terry also headed narrowly wide as Chelsea built momentum, but there remained the ever-present threat from Barcelona despite their flawed attempts to seemingly score the perfect goal.
Drogba appealed for a penalty when he clashed with Abidal, but Ovrebo ignored his claims - much to the obvious disgust of Chelsea's high-maintenance striker.
Barcelona suffered a setback after 29 minutes when defender Alves was booked for a needless foul on Ashley Cole, a yellow card that rules him out of the final.
Chelsea, predictably, came under pressure in the opening exchanges after the break, but they broke away to great effect, only to see Drogba waste a perfect chance to double their lead.
Anelka set him up 12 yards out, but after evading Barcelona's defenders Drogba shot against the legs of Valdes, with Florent Malouda striking the rebound into the side-netting.
Drogba was again left appealing in vain for a penalty after colliding with Yaya Toure, but Barcelona's giant midfield man looked to have just got a touch on the ball, despite referee Ovrebo feeling the full force of Stamford Bridge's fury.
Ovrebo was on the receiving end of Barcelona's anger after 65 minutes when he sent off defender Abidal after what only appeared to be an unwitting tangle of legs with Anelka
Chelsea were forced to make a change of their own seven minutes later when Drogba, a forceful physical presence all night, suffered a knee injury and was replaced by Juliano Belletti, who scored the winning goal for Barcelona in the Champions League final against Arsenal three years ago.
Ovrebo was in action again 14 minutes from time when Alex was deservedly booked for a cynical foul on Messi, again an offence that would have kept him out of the final.
Chelsea had made countless penalty appeals, but they looked to have a real case when Pique handled under pressure from Anelka, but once again referee Ovrebo was in no mood to point to the spot.
As the game entered the final minutes of stoppage time, the one moment of magic Chelsea feared from this gifted Barcelona side was produced to steal their dreams of a second successive final away from them at the last gasp.
Chelsea struggled to clear the ball away from their own penalty area and Iniesta sent a rising 20-yard drive past Cech into the top corner to spark chaotic scenes on the touchline.
And when the final whistle blew, Drogba marched on to direct his tirade at referee Ovrebo - it was an act that only increased the sense of anger and injustice on the air on a night of bitter disappointment for Chelsea.
ciao