Tonight the Hoops face French club Rennes in the Europa League and Lennon indicated that he is worried about the back four against a side that has the ability to score freely.
"It would worry me no matter who we were playing," Lennon said of his defence.
"We have to defend better than we did last Saturday (3-3 draw with Kilmarnock), that's for sure.
"I know Rennes are an excellent side. They are very exciting going forward.
"But we've got exciting players and we can cause them problems."