The 29-year old winger stepped up to the spot in the 81st minute when the scoreline was 1-1 with Spartak Moscow in the final group fixture of the Champions League and hammered it in off the underside of the crossbar to put the Hoops into the next phase of the competition.
Celtic required a win at home over the Russian club to qualify for the round of 16, meaning plenty was riding on Commons' penalty, and Lennon says he did not want to watch after seeing his side miss a few from the spot in recent matches.
"I didn't watch it - I turned my back on it! I've seen the last couple of penalties and we've missed them so I thought better of it this time," he said.
"I saw (first team coach) Garry Parker turning his back and thought I'd do the same. I just waited for the roar to go up. But Kris showed great mental strength to step up there and take it.
"He was obviously aware of the significance of the penalty but his penalty epitomised him tonight. I thought he had a fantastic game for us.
"At that point you want to celebrate but we still had work to do and we saw the game out well."