The England centre started for the Tigers at Welford Road on Friday after spending the previous three games on the sidelines with a groin problem.
With Leicester failing to win during Tuilagi's absence, Cockerill has praised the 23-year-old for his positive influence on the squad.
"You put Manu on the teamsheet and it hurts the opposition and lifts the morale of the team and the confidence of the side," he told BBC Sport. "Manu is world class. He hadn't played for a few weeks and he looked good, looked fit - he came back in good nick."
Leicester start their European Champions Cup campaign this Saturday when they host Ulster.