The Celtic star said that playing again Barcelona in the Champions League has given him the belief to take on anybody on the pitch.
"Different players pose different challenges and playing against the types of players I played against last week, Xavi and [Andres] Iniesta, the challenge with them is to get a kick of the ball," Sky Sports News quotes him as saying.
"But it gives you a lot of confidence and you have to take that into international football. That can only help and give you the belief that you can compete with these types of players, hopefully do well and get results."
Scotland sit in fourth place in Group A.