The Premier League side face League Two Bradford City at Wembley on Sunday afternoon, with the Swans clear favourites to claim their first major trophy.
Right-back Rangel was part of the Swansea side which beat Reading in the 2011 Championship playoff final and he hopes that the players can cope with the occasion.
"I think you always have the pressure," Rangel told Sky Sports News. "This time we are not the underdogs, we know that. At the end of the day, it's the cup final and it's all about emotions.
"Winning promotion from the Championship there was one of the highlights of my career. We are going back now and have the chance to experience it again.
"All we have to do is go to Wembley and perform. The most important thing is to win it. You don't want to go there and just play it. You just have to think what you would feel like if we went to Wembley and didn't win it. We would feel so bad."
Swansea defeated Chelsea in the semi-finals to set up the clash with Bradford.