The Hoops boss, as promised, made nine changes with this week's first leg of their Champion League last-16 tie against Juventus in mind, and was rewarded with a convincing display.
Lennon said: "I am delighted and I think you saw a wee glimpse of what is coming through."
Debutants Tom Rogic and Rami Gershon especially caught the eye, with the 20-year-old Australia international, claiming the man of the match award. Israel defender Gershon also grabbed his first Celtic goal to send the visitors ahead, after they fell behind to Nick Ross' early opener which had been cancelled out by Kris Commons.
Defender Marcus Fraser started in the SPL for the first time while there were rare starts for Paddy McCourt, Dylan McGeouch and Venezuelan striker Miku, who grabbed the third with eight minutes remaining.
Lennon added: "Marcus Fraser, Dylan McGeouch, Rogic - young players who I thought were fantastic today. Tom has settled in very quickly. You feel sometimes that there will be a wee readjustment period but he has settled in very quickly.
"We know Rami is powerful in the air and he scored a great goal.
"He had a great debut. And the players on the cusp of the first-team squad like Thomas Rogne and Miku came in and did well. To come here to a side in second place who were playing their first team, and to win with that team we had, speaks volumes for the performance of the players."
Caley boss Terry Butcher was not surprised that, in the circumstances, Lennon utilised his squad although he claims it did not make pre-match preparations any easier. "I would have done the same but I haven't got nine players to put in," he said.
"But I couldn't do any team talks before the game because I didn't have a clue what they were going to do - and when I got their team I still didn't have a clue. It was a good test for our players."