Parma trumped Napoli 1-0 on Sunday thanks to Marco Parolo's fine strike from the edge of the area in the 55th minute, which left Benitez's team on 64 points in third, 12 behind second-placed Roma.
Benitez remains convinced Napoli will finish third, as they have a nine-point gap on fourth-placed Fiorentina with six games to play, but the Spanish coach declared the Naples club does not yet have enough quality to challenge the likes of Roma and leaders Juventus.
"We have a team with quality, it has its strengths and weaknesses, which we need to analyse and learn to improve. Lack of consistency in a game is one of those things," Benitez told Sky Sport Italia.
"Every player has his characteristics and it's not easy to change everything. We changed many things (before the season), are in third place, but there's a long way to go yet until we can create a team that has the right mentality to win every game.
"That is what I want and what I'm working towards.
"I still consider this a very, very positive campaign. However, you can tell we are missing something.
"We won't finish second, as Roma win those games that we do not. This is the reality and we have to work every day to improve but in the meantime we can lock down third and prepare for the Coppa Italia final."
Napoli will take on Fiorentina in the Coppa Italia final on May 3 as Benitez aims to win his first piece of silverware with the Neapolitans.
The 53-year-old Spaniard was disappointed his team failed to convert their dominance into a victory in Parma as Napoli had 57 per cent possession and took 11 shots to five.
"We are all disappointed to lose a game that was under control in the first half and at the end of the day Parma only had one shot on goal," Benitez said.
"We had a great chance and we missed it."
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