But his biggest fear must be, as a 60,000 sell-out stadium gets ready for take off, his players forget to fuel up and buckle themselves in for the ride.
Lennon's men have become masters at switching performances on and off when it suits them throughout this season so far; dire in domestic home duties against Kilmarnock, St Johnstone, Inverness and then Arbroath in the William Hill Scottish Cup.
Yet excellent in Europe over the course of the Champions League group stage that has them on the cusp of a historic achievement.
Lennon's failure to get a good night's kip tomorrow won't be as much about deliberations over team selection for the match against the Russians, but more to do with which Celtic team will turn up on the night.
Ever since the final whistle in Lisbon against Benfica last month, the school of thought has been that Celtic's entire thought process was geared towards one momentous 90 minutes against Spartak.
If they freeze, don't produce the goods and end up in the Europa League, get ready for a massive anti-climax, not to mention mounting pressure.
The domestic foul-ups will be excused with the Spartak game yet to be played out. However, should they now miss out, such is the fickle nature of football, people will be lining up to have a go.
When the group was drawn most Hoops followers would have bitten your hand off for a third-place finish and a crack at the Europa League after Christmas. But the expectation is now that Celtic should better Benfica's result in the Nou Camp on Wednesday night and make it to the knockout phase.
Five years ago, in what must seem like halcyon days now for the Rangers support, they were drawn in a group that was made up of Barcelona, Lyon and Stuttgart.
It was as tough as Walter Smith's side could have asked for. Fans lined up to say they would just be happy to compete and not be disgraced.
But they started with seven points from the first three matches and, all of a sudden, it would be a failure from that point onwards if they didn't get through.
Of course, it eventually went pear-shaped. Rangers never took another point. They needed a draw against Lyon in the final match at Ibrox but were put to the sword almost single-handily by a Karim Benzema hat-trick and the last 16 was gone.
There was nothing but despondency in the air that cold Glasgow night – although that was soon forgotten when Rangers parachuted into the Uefa Cup and went all the way to the final in Manchester.
The stakes are high, big-time, for Lennon and his players on Wednesday. They have brought that upon themselves by over-achieving and now they need to live with it.
If the real Celtic turns up they will celebrate a famous night. If they don't? Watch the reaction...