Chelsea had the lead and all the chances until a desperation goal by Andres Iniesta sent 10-man Barca into the final against Manchester United.
Chelsea, whose defensive tactics in the first leg had been derided, took the lead on Michael Essien's early strike and was within a minute of returning to the final when Essien's errant clearance found its way to Argentine Lionel Messi, who spotted Iniesta at the top of the box. The midfielder did the rest, beating Chelsea goalie Petr Cech to the far post for the tying goal.
"We tried to win the game, we tried to create," said Barca coach Pep Guardiola. "We didn't create so much and it was hard against a Chelsea team we expected to press up more. But I have a lot of faith in my team. We keep going, we are consistent. We had 25 minutes with 11 against 10 men and still Chelsea stayed back. We continued to try to score and carried that goal threat until the final minute."
After Essien put Chelsea ahead, the Blues had a number of chances stopped by Barca goalie Victor Valdes and several appeals for penalty kicks waived off by Norwegian referee Tom Henning Ovrebo.
"Of course, players make many mistakes," said Chelsea manager Guus Hiddink. "Coaches make many mistakes and referees can make mistakes. OK, so it happens. It's all in the game. But when you see two, three or four situations waved away, then, yes, it is the worst I have seen."
The last-minute exit left Chelsea players devastated.
"It is quite a disappointment that we did not finish it," Hiddink said. "We can be critical of that. But it was the overall feeling of being robbed, of an injustice. That it why it was so hot and angry in the dressing room. I could fully understand the feeling of the players."
While Guardiola felt Chelsea might have had a case, he added that the home team should not have sat on its lead after Barca defender Eric Abidal was sent off in the second half.
"I can understand that Chelsea can be disappointed about the performance of the referee," Guardiola said. "I did not see the penalties they say there were but it is possible that there were. You have to give us credit, though. We tried to win the game, we tried to take the ball and create chances. We did not create so much but I expected Chelsea to create a little bit more pressure."
May 6 in London
Chelsea 1 Barcelona 1. Goals: Essien 9; Iniesta 90+3.
Chelsea -- Cech, Bosingwa, Alex, Terry, A.Cole, Essien, Ballack, Lampard, Anelka, Drogba (Belletti 72), Malouda.
Barcelona -- Valdes, Dani Alves, Pique, Toure, Abidal, Xavi, Busquets (Krkic 85), Keita, Messi, Eto'o (Silvinho 90+7), Iniesta (Gudjohnsen 90+6).
Referee: Tom Henning Ovrebo (Norway).
Red card: Barcelona -- Eric Abidal 65.
(Aggregate: 1-1; Barcelona wins on away goal.)