The Londoners went through with a 3-1 aggregate success against Benfica in the quarter-finals after a jittery 2-1 home win on Wednesday and will face the holders and favourites for a place in the Munich final.
Chelsea, who have won only one of their previous five semis, were largely ponderous against a Benfica side who played for most of the match with 10 men after stand-in skipper Maxi Pereira was sent off after 40 minutes.
A Frank Lampard penalty had Chelsea in control but Benfica made it 1-1 on the night through Javi Garcia after 85 minutes and after they missed a great chance for a second, which would have put them through on away goals, Raul Meireles scored the winner to set up a rematch of their controversial 2009 semi when an outplayed Barcelona went through at the death.
At stake for Chelsea is a place in the final against either Real Madrid or Bayern Munich with the spectre of a probable taste of the Europa League next season if they fail to win the competition for the first time.
Chelsea are currently fifth in the Premier League -- five points behind their London rivals Arsenal and Tottenham Hotspur, who they also meet in an FA Cup semi-final on April 15, three days before the first leg of their Barcelona semi-final.
They have a harder run-in than either Arsenal or Spurs with away matches against Arsenal and Liverpool and a home match against Newcastle United to come among their seven remaining league games.
There is pressure from behind too as Newcastle are in excellent form right now and level on points with Chelsea in the battle for the all-important top four places.
While their results have improved since Roberto di Matteo took over as caretaker coach following the sacking of Andre Villas-Boas a month ago with seven wins in nine matches, Chelsea's form has not significantly altered as Wednesday night proved.
With the cushion of the early goal and against 10 men they had the chance to turn on the style and produce a confidence-enhancing performance. Instead, as Di Matteo said afterwards, they lacked sparkle and made life very hard for themselves by failing to score a second goal to kill off Benfica, who in contrast, were full of flair and invention.
To their credit, Chelsea have done something that only Barcelona can match in recent times -- reaching their sixth semi-final in nine seasons, but as their Spanish winger Juan Mata admitted afterwards, they will need to play far better against Barca to remain in the competition.
"Everyone knows they are the best team in the world right now but anything can happen over the two legs. I think we can beat them, but we will need to be sharper and play better to achieve that result, but I believe we are capable," he said.
Benfica coach Jorge Jesus gave Chelsea little chance against the reigning European champions, who are bidding to become the first team since AC Milan in 1990 to lift the European Cup in successive seasons.
"I cannot understand how they have gone through and we are out," he told reporters."
"What hurts me is that we have knocked out better teams than this Chelsea, that's what leaves me with a certain sense of revolt. I may be wrong but I believe Chelsea have no chance against Barcelona."
That's a view shared by Chelsea's former manager Jose Mourinho, whose Real Madrid side will face either Barcelona or Chelsea in the final in Munich on May 19 if they beat Bayern in their semi-final.
Mourinho said after his side knocked out APOEL Nicosia 8-2 on aggregate on Wednesday that if Real reached the final he expected them to play Barcelona.
"Barcelona aren't the favourites, they are super-favourites," he said.
"Let me be honest, I don't think the final will be a Real Madrid v Chelsea final. It could be Bayern or Barcelona, I just don't think it will be Real Madrid v Chelsea and we know why."