"But I expect them to see a different mentality and a different animal tomorrow. It is a new experience for my players, but there has to be a consistency in their performance."
It's hard to argue with Lennon's assessment that the men dispatched by Benfica boss, Jorge Jesus, to run the rule over Celtic at the weekend would have delivered a far-from-flattering report.
Whether or not that causes the Lisbon side to pack complacency along with their kit as they head into Glasgow today, only time will tell.
What is not open to debate is that a repeat of the performance given by Celtic at McDiarmid Park, and in a few other SPL games this season, will make collecting all three points in their opening Group G game near-impossible to achieve.
The manager has made his feelings very clear, both in the privacy of the dressing-room and in public, that picking and choosing the games in which you want to give of your best is simply not an option.
The Celtic side which Martin O'Neill regularly took into Champions League and Uefa Cup action – of which Lennon was an integral part – did not allow their standard to drop between big European matches.
And the side Lennon is moulding will not be allowed to allow such a worrying fluctuation in form, either.
But the boss is steadfast in his determination not to use the achievements of the group led by Henrik Larsson, Chris Sutton, John Hartson, Paul Lambert, Johan Mjallby and himself as a stick with which to beat his fledgling side.
"Yes, that team did know how to win in the league at the weekend and in Europe in midweek, but I am not going to make comparisons," he insisted.
"It was two different teams. This is still a relatively newish team. But there is no doubt it is a mentality thing. They have to buy into it. I have spoken to them about this, and that's it."
By that's it, Lennon means no argument will be entered into. He has made his position clear, and now the onus is on the players to show they have not only listened, but taken it upon themselves to make amends both to the manager and the supporters.
"They definitely owe the supporters a performance after the weekend," said Lennon. "The fans were good at McDiarmid Park, and deserved a lot better. That was as poor as our team has played for a long time."
Lennon is confident that the prospect of playing in the Champions League will ignite everyone at the club, and acknowledges that they will have to be at their very best if they are to get off to the winning start they need in what is going to be a very testing group.
The news that Benfica skipper, Luisao – who Lennon knows well from his jousts with the Brazilian giant in previous meetings between the clubs – will have to sit out this game and the following three in the Champions League as part of his two-month suspension for pole-axing a German referee in a pre-season friendly has been received well in the Celtic camp.
"That's a big bonus for us because he is the captain of the team and very experienced," admitted Lennon.
"Luisao is a quality player, a Brazilian international, so it's a help to us that he is not playing.
"But I am not taking anything for granted as Benfica are a quality side.
"And we have to pick ourselves up and do a lot better than we did at Perth. We have to really, really focus on this game now."
With a difficult trip to Moscow to face Spartak coming up next before the daunting double-header against Barcelona, it is imperative that Celtic get points on the board to avoid finding themselves playing catch-up.
Lennon is justly proud of the club's home record, and the fact that, in their three previous visits to Parkhead, Benfica have never taken so much as a point, nor scored a single goal.
However, the manager will continue to emphasise to his players that nothing is given at this level, everything must be earned.
It will require all 11 who start, plus those who come on, to play at their optimum if the quest for a top-two spot in Group G and the place in the last 16 that will bring is to get the launch-pad it requires.
"You can't pick and chose your games, and that seems to be what is happening at the minute," said a concerned manager. "I have no doubt they will all be up for the game tomorrow. But they should have been up for the game on Saturday. Instead they gave a needless performance."
"The only spark for me was Kris Commons, in an attacking sense," Lennon lamented. "James Forrest had as poor a day as I can remember. Victor Wanyama and Charlie Mulgrew didn't really affect the game the way they can.
"Emilio Izaguirre looked as though he was lagging a bit, which was understandable [as he had been on another long-haul sojourn with the Honduran national team].
"But, I do worry that, when these boys are away on international duty, they forget where their priorities lie."
Tomorrow night, when they walk out on to the Parkhead pitch and hear the Champions League anthem booming around a stadium packed with expectation, optimism and pride in equal measure, they will be left in no doubt.