The Spanish outfit found it difficult to break down a stern Celtic team, but a Cesc Fabregas header 15 minutes from time secured all the points for the away side.
"We know it is always difficult here. We knew it would be tricky and that we would have to work hard, but in the end we are very happy with the victory, which is very important to us," Pedro told reporters at a press conference.
"When the game and the score is so tight, we know that any move, any set piece, a corner, could be dangerous for us.
"We had a few more chances in the second half to kill the game off, but again their goalkeeper [Fraser Forster] has had a great game and in the end we should have won with a bit more to spare. We could not but we are happy with the win."
"We always miss [Lionel] Messi because he is the world's best player. It makes a difference when he is not on the pitch and let us hope he recovers quickly as he is an essential player for the team."
Barcelona have won all of their league and Champions League matches thus far this season.