The Scottish champions, guaranteed a Europa League spot after Barcelona beat Spartak 3-0 in Moscow earlier in the evening, will go through if, in their home game against the Russian club in a fortnight, they better the Portuguese side's result in the Nou Camp.
Lennon, who revealed skipper Scott Brown is set to undergo surgery on a hip complaint which could keep him out for 10 weeks, and who will be without midfielder Victor Wanyama for the visit of Spartak after he picked up another booking, said: "I think Benfica are capable of getting a win in Barcelona, for they are an excellent side.
"But we have to make them do that.
"I don't know what kind of mindset Spartak will be in, they might want to spoil our party, we have to be totally focused.
"What we have to do is win at home and make Benfica win in the Nou Camp which is no easy feat.
"No one gave us a prayer coming into this competition, these players have been exceptional, they have made a name for themselves and we are still in with a good chance of qualifying."
Brown has been battling all season with a hip complaint, only playing intermittently and usually in the big games, but had to succumb to the pain in the second half when he was replaced by Kris Commons.