The Scottish champions qualified for the last 16 of the competition last year but, with three points from five Group H games, are guaranteed to finish bottom of the section this time around.
However, former Celtic skipper Lennon, whose side are almost certain to retain their Scottish Premiership title to give them another tilt at the European football's elite club competition next season, wants his players to leave Catalonia with their heads up after the final fixture even if - as expected - the result goes against them.
"It is important, not just for the context of this campaign but next year, where we will have qualifiers in July," he said.
"Three points is not enough. I think we deserve more out of the group but we are going to have to play very well.
"We are going to need great discipline, concentration and athleticism and we have to be brave on the ball and even then it may not be enough.
"But we want to come away with some satisfaction if not the result.
"This is a great occasion and we are very much looking forward to it."
Barcelona coach Tata Martino believes speed will be key to victory.
The Catalan side need a point to finish top of the section after losing at Ajax in their last Group H game.
Barca have 10 points from five matches with AC Milan second on eight points ahead of their game against Ajax, who are one point further back.
"It is very important for us to finish first and I don't think any games are easy," said Martino.
"Every match has consequences and we need to be precise and quick on the ball going forward.
"I imagine most of the game will be squeezed into 30 or 40 metres of the pitch.
"We need to be well organised as well so as not to be caught on the counter by Celtic who are capable of quick breaks."
Barca scraped through 2-1 against Lennon's side in their group game at the Nou Camp last year thanks to a last-gasp Jordi Alba goal.
However, midfielder Sergio Busquets warned the Scottish champions that Barca have "learnt our lesson from last year".
"They have their style of playing, which is very different from ours," he said.
"The sooner we get a goal, the better, because they can close down at the back and make it hard for us.