Napoli boss Rafa Benitez admits Gonzalo Higuain is frustrated after defeat to AC Milan.

Higuain was visibly upset, often shouting at teammates and the referee, but improved after Duvan Zapata came on to partner him in attack.

"The game started badly for us, the team reacted well in the second half, but Higuain was disappointed at the way things went," Benitez told Sky Sport Italia.

"If Higuain did everything he did last season, it was in the same position he played tonight. We had more chances later on because Milan sat back in defence, but we had opportunities throughout and failed to score."