Napoli boss Rafa Benitez was left disappointed with their 2-0 defeat by Hellas Verona.
Veteran striker Luca Toni, 37, struck a brace in Verona's win.
"You could say we didn't start the first half well, or the second, and we paid a heavy price for that," said Benitez.
"Clearly I didn't prepare my players for this situation. We only did what we had to do for about 25 minutes in the first half.
"I was cross because I don't like to lose and I especially don't like to lose this way."