Goals from Alessandro Matri, Mirko Vucinic and Claudio Marchisio were enough to give the Italians the win in their first leg of the last-16 Champions League clash, and Lennon felt aggrieved that his side were not awarded a penalty for regular shirt tugging at corners.
"I thought [the referee] was poor," Lennon told Sky Sports News. "I thought he was very pro-Juventus. I was disappointed with his performance to say the least. It's not rugby we're playing, it's soccer.
"They were being fouled, manhandled. Every time one of my players tried to move he was held. He should have given a penalty on at least two occasions.
"I'd like to know what the interpretation of the rules are in Italy or Spain, because it's blatantly different to what they are in Britain from what I've seen tonight."
The second leg will be in Turin on March 6.