The 27-year old former Stoke City, Nottingham Forest and Derby County forward produced another stunning goal in yesterday's victory over Kilmarnock at Rugby Park to take his Hoops tally to 13 from 18 appearances in all competitions.
Lennon feels that Commons, who was purchased from the Rams in January after scoring 13 in 26 for the Pride Park club in the first half of the season.
"I wouldn't have thought (there has been a better buy), not for £300,000," Lennon said.
"So we have been lucky in that respect, the players we have brought in this season have been magnificent.
"Kris is coming to the peak of his career.
"You almost get disappointed when he lashes a couple over the bar, he's that good.
"You can look at four or five of his goals for goal of the season.
"He has been tremendous, he has a tremendous work rate and he is always likely to pop up with a goal."