Facing Barcelona in the Nou Camp is the pinnacle of anyone's career, be it the man in the dugout or the men on the field.
Lennon accepts this particular examination has arrived a bit sooner than he would have chosen as he and his players are still getting to grips with the rarefied atmosphere to be found in the Champions League.
But, just as he did as he approached the tie against Spartak in Moscow, the Parkhead boss is today leading his squad to the Catalan capital relishing the prospect of testing themselves to the limit.
The fact they do so on the back of a 5-0 demolition of St Mirren is not dismissed lightly by Lennon, even though it is clear that comparing the two challenges is akin to safely negotiating the Kingston Bridge and suggesting you are ready to compete in a Grand Prix.
Nevertheless, Lennon gave his players 10 out of 10 on Saturday, and is hoping to be in a position to award them another gold star tomorrow night.
He is not blinkered, however, and insists he is going into this Group G game with his eyes wide open.
"Good teams make you look ordinary, and they find your weaknesses eventually and capitalise on that," said the man who flew out to Spain immediately after the win at Paisley to watch Barca defeat Deportivo La Coruna 5-4.
"Which is why it was pleasing to see that we had 14 outstanding performances on Saturday against St Mirren. That will put them in good stead for this match against Barcelona.
"Now, I don't care what level you are playing at, it's the sign of a good team if you can all be at the top of your game. I'm not saying we are going to play like that tomorrow night. We are not, and we know that.
"But it can't do the players any harm at all to go into this match having performed to that standard."
Goals from Gary Hooper, Efe Ambrose, Tony Watt and a double from Victor Wanyama certainly ensured the feel-good factor was spread widely.
But it is the win in Moscow before the international break which will carry most currency going into tomorrow's game, the first in a double-header against the favourites to win the Champions League.
"We have given ourselves a good platform in the group with the four points from the matches against Benfica and Spartak Moscow," mused Lennon with no little satisfaction.
"We know that this game could change the landscape of the group. We totally understand that. And we haven't budgeted for getting anything. But, we feel some of the players are playing right at the top of their game at the minute.
"I appreciate that taking that from the SPL to the Champions League is a difficult thing to do.
"But, we've done it already this season, and I think there is a little less fear factor in this team because they are relatively inexperienced. There is also a naivety about them at times, but you can't have everything."
Which is why the lessons they are learning in the master-class which is the Champions League – added to the education they received in last season's Europa League run – are invaluable in their development individually and collectively.
Lennon is also cutting his teeth as a manager at this level, and conceded: "This has probably come a bit early for us all. But, listen, it's a great challenge. It's great for the supporters. And for the players it is a big game and occasion.
"But I don't want them walking round the place thinking, 'This is great to be here'. "I don't want them taking photos or arranging to swap shirts before the game, or anything like that. I just want them to focus on what they have to do, then take it from there."
Lennon knows from his own playing career how occasions like this can affect individuals. The low average age of his squad could leave them susceptible to stage fright.
But, along with seasoned campaigners Johan Mjallby, Danny McGrain and Garry Parker, the manager will work hard to mitigate against this.
"I'd had international football against really good teams when I first played in big games like this," recalled the man who joined the Hoops when he was 29.
"It's a different style of football to what you get when you face the likes of Barcelona in the Champions League, but it is still hard. I was a lot more experienced than some of these lads are. But all we can do is pass that experience on.
"I enjoyed it when we played Barcelona, especially when we beat them over two games (in the Uefa Cup in 2004). That was fantastic for everyone involved. But, since then, Barca have improved even more.
"They are going well in the league and have maximum points from their Champions League games. Listen, they are the best team in the world at the minute."
On Saturday night, however, Lennon saw for himself that the spate of injuries to key defenders, including Carles Puyol and Gerard Pique, have left Barca vulnerable at the back.
After a whirlwind start, during which they raced into a three-goal lead inside the first 18 minutes, Deportivo La Coruna pushed them all the way before finally going down 5-4.
A hat-trick from Lionel Messi was vital in securing the three points, but Lennon was given much food for thought.
He understands the international break can upset a team's rhythm, even one packed with as many talented players as Barca. But, Lennon was delighted with the way his own league of nations got right back into the groove at New St Mirren Park after returning from their national service.
"It was pleasing that the players picked it right up again after the international break," he said. "They are growing together. The new players coming in are starting to look better.
"You can see what Miku, Lassad and Ambrose bring to the team. So the squad is vibrant. And with Joe Ledley and Beram Kayal – who are important players for us – back again, it made us stronger.
"We obviously missed James Forrest and Georgios Samaras, and had to change the shape of the team a little bit. But, when you have someone like Tony Watt coming in full of running, pace and power, that's a bonus for us."