Despite the late setback, the travelling support continued to back the team and the players responded by crossing the pitch to applaud the 5,000-plus who made the journey to Spain.
Speaking on the club's official website, Lawwell said: "It was a tremendous occasion and one that we were delighted to be involved in.
"The UEFA Champions League is the stage which Celtic strive to compete on, and we have shown this season that we deserve our place alongside Europe's elite.
"To play a team of Barcelona's quality, rightly regarded the best club side in the world, is the toughest challenge we can face, but Neil and his players rose magnificently to it.
"And they were desperately unlucky not to get what we all felt would have been a well-deserved point for our magnificent efforts.
"We now look forward to welcoming Barcelona and their fans to Glasgow in two weeks' time.
"As for our own supporters, they have shown once again why they are so special and so important to the club. Their backing for the team was tremendous and I'm sure they were very proud of the performance the players produced.
"To have so many fans in Barcelona supporting the team is a tremendous boost for Neil and the players, and I know it's something they all appreciate."