Didier Drogba's first-half goal has given the Premier League side the advantage ahead of next week's return leg at the Nou Camp.
"We had to be patient, we didn't touch the ball in the first 10 or 15 minutes and we had to work very hard. It was a tireless performance," Terry told ITV Sport.
"It will be tough in the second leg, they had a lot chances but quite clearly they will have opportunities there. We are not in awe of them, we respect them but another performance and we'll be okay."
Chelsea travel to Barcelona for the second leg on Tuesday.