The home side found themselves under pressure for large spells of the game but managed to come through a fraught and frantic 90 minutes with a precious point.
The result is enough to keep Rangers level on points with the Catalan giants at the top of Group E.
"I am obviously delighted with the result," said Smith. "In a defensive sense we did extremely well over the 90 minutes.
"For us, it was an excellent result."
Daniel Cousin had the thankless task of playing in the lone striker role and Smith said: "I felt a bit sorry for him, he had to handle a difficult situation on his own."
He added: "In other matches we have created more opportunities but we need to remember that we were playing against the best side in the group.
"Although we didn't create a lot of clear-cut chances, Barcelona didn't have that many opportunities either."
Despite the result, Smith is taking nothing for granted and insists Rangers cannot yet take qualification from the group as a given.
"Lyon won against Stuttgart tonight and the section is going to be tight by the looks of things," he said. "I am delighted to be sitting in the position of not having lost after three games.
"The players have worked extremely hard and I don't think any other team has worked as hard as us."