Napoli coach Walter Mazzarri was disappointed with his side's loss to Liverpool on Thursday.
Liverpool won the game 3-1, thanks to a second half hat-trick from Steven Gerrard.
“We were not up to it when the key moments mattered,” Mazzarri told Calciomercato.com.
“The hype surrounding the match conditioned the referee, as there were lots of tough fouls awarded.
“The foul by [defender Salvatore] Aronica [in the penalty box] was a tough one to award, but they also made some tough tackles.
“Overall, we played a good match, but it is a shame that it ended like this.”