The Hoops' elimination in last place of the Champions League Group H was blamed by many for the Parkhead club's refusal to source adequate replacements for summer departures Gary Hooper and Victor Wanyama.
But with Lennon in the market for a January striker, the Bhoys boss has dismissed suggestions he could swoop for Sunderland and Scotland international Steven Fletcher to boost his forward line.
Lenny also defended the club's trading record in last summer's signing market.
Lennon said: "It's not a marquee signing I'm looking for, it's a player or players that will bring us on and make us better. Look, we have resources now.
"We are in probably as strong a position as we've been in a long, long time, so it's important that we spend the money that's available and get the right quality in.
"Ideally you'd like to do that but clubs want to hold on to players and as much money as they can get.
"We're no different from any other club. I had a meeting this morning with Peter Lawwell and we worked away at the business we want to do, as best we can.
"People might laugh at this, but I think the squad is thin and I want to add to it in certain areas.
"There is no question that there will be players leaving and there will be players coming in.
"We are trading as well. I don't need to sell to do that but ideally you don't want to clog it up either.
"The market is difficult but I would say that we've got two thirds of it right. We sold a lot of players in the summer and we will sell again eventually.
"We have huge assets in the team - again we haven't had that for quite a while - but at the same time we still want to add to that and what I want is real, genuine quality.
"And if we have to spend a bit of money, which I think we have, then we'll spend it if we can get the right player in."
Lenny continued: "You have to have a list of targets, because eventually you will come to a point when if your first choice isn't coming, then you look at the next one."
But the Hoops gaffer poured scorn on a reported swoops for Black Cats strike ace Fletcher.
Lennon said: "I don't know where the story has come from. Again, I can't talk about players who are under contract at other clubs and I'm not going to talk publicly about players at other clubs.
"He's obviously a fine player but he cost Sunderland £11million and I don't have that type of money, believe me."
When it came to the possible exit of Georgios Samaras and Joe Ledley, Lennon said: "Nothing has changed."