The Aviva Premiership champions now sit fifth in the table, and Cockerill feels that they are making too many mistakes at the moment.
"We are disappointed; it was a pretty ordinary game with error after error," Cockerill told reporters. "The weather conditions were difficult but we missed crucial kicks and we went to sleep for their try. These things cost you and our performance was below average.
"We have the whole of our first-choice back-line out and a number of key forwards but we came with a side that should have played better. It wasn't a disgrace but I expected a little bit better than that."
Tigers host Harlequins at Welford Road next Saturday.