"We haven't designed a plan of attack because it depends who plays for Barcelona," he said. "We know what Barcelona can do - we have to play our best possible match.
"We will field the strongest team possible. We got a good result in our last Champions League match so we have nothing to lose.
"We're not here on holiday or for the tourist attractions. It'll be a tough 90 minutes for us but it will be for them too.
"There's always pressure for any game. We have grown as a team over the last year. We haven't really prepared any differently for this game."
Celtic are currently second in the group with four points from two matches, two points behind leaders Barcelona.