"Barca is obliged to play an attractive game and there is no other way I know for us to play," Guardiola told a news conference at the Nou Camp on Monday.
"Tomorrow is a big chance for us to show the world our style and we will be trying to seduce with our way of playing," he said.
"Our principles are not for renouncing and we will never give them up as long as I am coach."
Barca, Champions League winners in 2006, are the top scorers in this season's competition with 29 goals and have the leading scorer in Lionel Messi, part of a lethal attacking combination with Samuel Eto'o and Thierry Henry.
The last two visitors to the Nou Camp, Lyon and Bayern Munich, conceded five and four goals.
Guardiola, who won the European Cup with Barca as a player in 1992 and is in his first season in charge, noted that Chelsea's physical strength and speed would make them hard to break down.
"There are always things to mull over if you are playing a team like Chelsea but I am a very optimistic person," he said.
"I am just as happy as a boy living his dream. I don't know if this moment will ever be repeated so I am just going to enjoy it. I am confident we will respond well."
Midfielder Xavi, one of the key creative forces in Guardiola's side, said Barca fully deserved their place in the last four, where they are the only non-English club for a second consecutive year.
"We are not here by chance," the Spain international said, adding that the standard of the Primera Liga was better than England's Premier League.
"Technically and tactically speaking I think the Spanish league is better," he said. "But the result of a single match won't settle that debate one way or the other."
The second leg is in London on May 6 and the winners of the tie will face holders Manchester United or Arsenal in the final on May 27 in Rome.
