The Northern Irish manager may have overseen a surprise 2-1 victory over the Camp Nou outfit last season, but he is expecting a sterner test when the two sides meet on Tuesday
Barca have a perfect record in La Liga this season, scoring 24 goals in their seven wins, and also netted four times against Ajax without reply in their Champions League opener.
And while the Scottish champions recorded a famous 2-1 victory over Tuesday's opponents in last season's competition, Lennon believes his side have a tough task trying to stop Gerardo Martino's men this time around.
|22/1||Celtic are 22/1 with BetVictor to beat Barcelona 2-1
"They're not like any other team. Barcelona, in my personal opinion, are a class above, and have been consistently the best club side for 10 years now.
"Barcelona don't change their system, their style of play and that is what they believe in. When they get the ball in the final third, the speed of the ball is phenomenal at times."
Celtic opened their Champions League campaign with a 2-0 defeat to AC Milan, but their hopes of causing another upset against Barca have been boosted by the absence of Lionel Messi.
Lennon believes his side need to start picking up points in the competition sooner rather than later, and feels the Spanish champions will still pose a significant threat, even without the Argentina international.
"If we don't prevail in this game, and Milan beat Ajax it will be increasingly difficult [to progress]," he continued. "But it won't be the end of the world if we don't win with the Ajax double header and Milan still to come here.
"Like last year we didn't budget for anything out of the Barcelona games, but if we do get something it would be huge going forward.
"[Messi's absence] is obviously very good news for us because for me he is the best player in the world. But it is also tinged with sadness as it is always good to see the best players here in Glasgow."