With just five players coming in, including the return on a permanent deal of goalkeeper Fraser Forster, the target was to emerge with quality rather than quantity in a squad which would be asked to challenge on domestic as well as Champions League fronts.
The danger was always that, if injuries hit – as they invariably do at some stage in the campaign – filling the breach might prove difficult.
That particular test came early for Lennon.
However, as the treatment room finally begins to clear after having its resources stretched to the limit – those taking up residence there in the first few months this term include Georgios Samaras, Beram Kayal, Joe Ledley, Scott Brown, Anthony Stokes, Gary Hooper, Charlie Mulgrew, James Forrest, Thomas Rogne, Mikael Lustig, Paddy McCourt, Dylan McGeouch, Miku, Lassad Nouioui and Filip Twardzik – the Celtic manager can take comfort from the fact those left standing did prove good enough to keep the club on track in every competition in which they are competing.
One of the keys to this is the adaptability of the players that Lennon has gathered around him. And Efe Ambrose is the latest example.
The Nigerian internationalist was signed from Israeli club FC Ashdod, ostensibly to add pace, presence and quality to central defence.
However, the 23-year-old has stepped into the team in central midfield – and has proved to be a smash hit.
Like Victor Wanyama, his ability on the ball and reading of the game allows Ambrose to switch between the back line and midfield with ease.
Mulgrew is another whose adaptability is being used to the maximum. With only a dozen games gone this term, the current Scottish Player of the Year has already turned out in central defence, at left-back and in the left side of the midfield.
Adam Matthews is another who has been moved up from full-back to the middle of the park, with Lustig doing likewise while the Swede has also stepped across to central defence, when required.
Samaras as well as Kris Commons are others who Lennon has fielded in more than one position, and this option has not arrived at the Celtic manager's doorstep by accident, but by design.
"At most of the big clubs, they have players who can play in different positions," said Lennon.
"If you look at what Sir Alex Ferguson has done over the years, sometimes he plays players in different positions."
The key is, of course, having the quality of player who can adapt. Pushing square pegs into round holes is a recipe for disaster, especially in the Champions League.
"They are all-round good footballers," Lennon explained in consideration of the men he is currently taking to places they never previously thought they might go.
"Ideally, they want to play in what they actually think is their favoured position.
"But we think we have got players who can adapt and do a specific job for us in specific games."
On first glance, Ambrose certainly fits the identikit.
And though he will face stiffer examinations than what was given to him by Irn-Bru First Division Raith Rovers on his home debut on Tuesday night, Lennon is satisfied that the rangy Nigerian will get even better as he becomes more accustomed to his new surroundings.
A brief substitute appearance against Dundee was followed by a 90-minute master- class in the Scottish Com- munities League Cup, and all of this without the benefit of any real opportunity to work with his new team-mates after only arriving on the eve of the opening Champions League game against Benfica. He was then handed a place on the bench to give him the chance to see his new team at close hand.
Lennon said of the man whom he signed for £1.2million as the transfer window closed, but was unable to join up until the red tape was removed: "Efe had problems getting his work permit, and all that stuff.
"Now all of that is clear, he has been training with us for a week and has got to know some of the players.
"We knew what we were bringing in, and, thankfully, he showed that on Tuesday night."
Lennon had extensively studied Ambrose on DVD, and read copious reports compiled by his scouting team.
But, as ever, it was not until he saw him in the flesh that he realised the full extent of what he had to offer.
"Efe is a good athlete, and he is quite deceptive as well because he is quite thin, but is very, very strong," said the manager.
"Tactically he is good, too. He passes it simply and well. He sees the danger and picks up the lose bits and pieces. He showed this while playing in midfield against Raith Rovers.
"But we could use him at centre-half because he can do all that and has blistering pace.
"All in all, we think we have got a good player for the money we have spent."
Getting full value for any outlay is an essential part of Lennon's job, and his track record in this department continues to impress.
Hooper is leading the way on this front, with the striker acquired for just £2.4m now worth his weight in gold for the Celtic manager.
Even he has had to show his adaptability, playing as a lone striker in European away games, and often being asked to drop back while operating with a partner at home.
This ability to move key pieces around in what is a tactical game of chess which competing at the top level becomes is a challenge Lennon embraces.
With Ambrose, Miku and Lassad further strengthening his hand and options, and the injury list reducing by the day, it is little wonder he is looking forward to the tough October schedule – which includes Champions League games in Moscow and Barcelona – with fresh optimism.