John Terry issued an immediate apology to his Chelsea team-mates for the red card which left them facing a backs-to-the-wall battle against Barcelona.
The Blues skipper was given his marching orders by referee Cuneyt Cakir in the first half of their UEFA Champions League semi-final second leg for a blatant knee into the back of Alexis Sanchez.
But despite their numerical disadvantage, the Stamford Bridge side hit back from 2-0 down to draw 2-2 at Camp Nou and progress 3-2 on aggregate.
Goals from Sergio Busquets and Andres Iniesta either side of Terry's moment of madness put the Catalan club in control, only for Ramires to put the Blues back on top with a sublime chip shortly before half-time.
Lionel Messi then fired a penalty against the bar early in the second half and later hit the base of the excellent Petr Cech's post, before substitute Fernando Torres sparked scenes of jubilation with a breakaway strike in added time.
Terry, who will now miss the 19th May final through suspension, admitted after the match that he had let his team-mates and the club down.
The Blues skipper Sky Sports: "I've seen the replay and it does look bad. I'm not that type of player to intentionally hurt anyone.
"I've raised my knee which I shouldn't have done with hindsight, but hopefully the people out there who know me know that I'm not that type of player.
"I'm disappointed, but absolutely delighted for the lads. To come here and perform the way they did and get the result they did with 10 men...
"I feel as though I let them down. I've apologised to them and I want to apologise to the Chelsea fans as well.
"The lads deserve to be there. It's so important for the football club. Three or four months ago no-one would have predicted us being in this position where we are today.
"I've let the lads down, they've performed brilliantly, so hopefully this won't take away from their performance and the way they've worked together as a team.
"It's what this football club deserves. We have had a bit of luck in this competition and long may it continue."
Which was the best Champions League comeback?
Man Utd v Bayern Munich - 1999 final
Liverpool v AC Milan - 2005 final
Barcelona v Chelsea - 2012 semi final