Napoli coach Walter Mazzarri has warned his troops that they cannot afford to play as they did during the 3-0 home loss to Viktoria Plzen on Thursday.
The Partenopei stand on the brink of elimination from the Europa League thanks to the shock defeat to the Czechs, and the 51-year-old has admitted that his side did not approach the game in the right manner.
“You could see we didn't have the right mentality. We cannot step onto the pitch like that," he told Sky Sport Italia.
"In the second half we created seven clear goal-scoring opportunities. Viktoria, however, scored two goals with two and a half chances.
“Today it didn't matter whether we were using three or four at the back, as we simply didn't get on the ball with the right attitude. Some players didn't step on to the field the right way.
However, Mazzarri was quick to turn his attentions towards Sunday's clash with Sampdoria at the San Paolo as they look to bounce back immediately.
"Tomorrow I will have to speak to the lads and hear from the horse’s mouth what went wrong," he continued.
“We hope to get straight back on track in two days against Sampdoria, even if today we contributed to the performance. We were superficial.
“I want to remember what happened with us against Chelsea last season in the Champions League, as they seemed done for too."