Lennon watched on as Lewis Morgan, Ryan Christie and Mikey Johnston all made the scoresheet to extend the Bhoys' unbeaten run in the competition, having taken 13 points from the 15 available to top Group E.
The result means they have European football to look forward to after Christmas and the Scottish champions should get a favourable draw after becoming the first Celtic squad to finish as top dogs in the pool stages.
A trip to Romania to face CFR Cluj rounds off their group stage campaign and Lennon can afford to rest some of his players for the game.
Such a position is a rare one for a Celtic boss, with the club usually battling against the tide in Europe.
However, the Northern Irishman believes qualifying from a group that also includes Lazio with a game to spare shows how far his side have come.
Speaking afterwards, the 48-year-old hailed his team's improvement and sees no reason why they cannot make the latter stages of Europe's second-tier competition.
"It's a landmark night for us. We've never done it before (winning the group), whether that be Europa League or Champions League," he is quoted as saying by the club website. "That's fantastic and it means we can maybe get a better draw for the last 32.
"We've definitely improved our results and performances (in Europe). There's a long way to go in the competition, and the last 32 is a long time away but we are excited."