The Swans head into the semi-final second leg at the Liberty Stadium holding a 2-0 advantage over the Londoners and will look to finish the job on home soil.
Spanish right-back Rangel, who joined Swansea for just £80,000 when they were a League One club in 2007, knows his side's fate is in their own hands.
He said: "We know we have a big advantage, we are 2-0 up and if you look at Chelsea they are thinking they have to come to the Liberty Stadium, which is not an easy place to come to, and score three times.
"We are not favourites but we have an advantage, we are confident at home and it is in our hands.
"We are in front of our supporters and we want to make history."
Meanwhile, Rangel admits he has been embarrassed by the media exposure given to his feeding of the city's homeless.
The Spaniard and his wife Nikki were moved to act after overhearing a manager at a local sandwich chain say he would have to throw out their produce as they were about to close for the night.
The pair asked if they could take the food to feed the homeless in Swansea and, after asking for suggestions of where to distribute the food on Twitter, they were able to help a local charity shelter.
He said: "I am a bit embarrassed, I have mixed emotions. We did not want any press, me and my wife. We just did it for the fact we thought at the time it was a good idea, we did not want anything from it.
"We know it has made a big impact, we are grateful that people have appreciated what we have done, but we are embarrassed because we don't deserve it.
"The people who work 24/7 in those shelters deserve more praise than us."