Antonio Conte's first game in charge of Napoli ended in humiliation, as Verona won 3-0 on the day.
Raspadori told DAZN: "I think the episode of the goal in the second half was decisive. We weren't able to react, mentally we went out a bit from the match, we didn't have the reaction we needed to have. This was the main mistake, each of us must be aware of this, we have to work because we are not this way. We have to work and try to recover immediately for the next match.
"I don't think we were physically bad. When your head isn't fully 100% because you suffer a negative episode, consequently I think your body suffers. We need to be able to take this step of resetting last season and starting again from a first half that it was done well, where we didn't concede anything, knowing that we are not the ones who took the field today."
On Conte's reaction, Raspadori added: "He is certainly not happy, but we are not happy either. We know that we have to work hard, in silence and with humility because, even if an extraordinary thing was done two years ago, it does not mean that things come from heaven now.
"We have to work and start again from the next training session with a different mind."