Third-placed Napoli clearly gained heart from beating Arsenal 2-0 on Wednesday and winning their fourth match out of six in Group F which also featured last season's runners-up Borussia Dortmund and former champions Olympique Marseille.
Missing out on the Champions League group stages is a huge blow for a Juventus side who could do with a new challenge after achieving domestic dominance under coach Antonio Conte, who has led them to the last two Serie A titles.
Napoli's Benitez, on the other hand, is still rebuilding his side following the signings of Raul Albiol, Jose Callejon and Gonzalo Higuain and the departure of Edinson Cavani.
After a good start, Napoli have taken only one point from their last two games and face their former coach Walter Mazzarri when they host Inter Milan on Sunday (1945 GMT).
Mazzarri transformed Napoli in his four years in charge, leading them into the Champions League for the first time.
"I think we should look at this as a stage during our growth process and regard it as proof we are on the right track," said Benitez after the win over Arsenal.
"The supporters should be proud of what Napoli have achieved."
"We did very well in Europe because there are more spaces than in Serie A," he added. "Our Champions League campaign has been very good and to be so high up the Serie A standings with a new team is an achievement.
"I think the process means bringing in young players who can be here for many years and be part of the long-term project.
"Against Arsenal, we proved that with two or three additions we can compete in Serie A and at another level in the Champions League. In Serie A, with Juventus and Roma doing so well, our results don't seem as impressive, but the truth is we've done very well."
Juventus host promoted Sassuolo in a game that has been moved to Sunday (1730 GMT) from Saturday because their match in Galatasaray was abandoned on Tuesday and replayed Wednesday.
Conte, whose side reached the Champions League quarter-finals last season before being outclassed by eventual winners Bayern Munich, said Juventus had to bounce back.
"We have to plunge back into Serie A and the disappointment has to spur us on domestically," he said. "We have another two games before the Christmas break and will then start to think about the Europa League.
"We mustn't forget that this side has bounced back after twice finishing in seventh place," he added, referring to the two seasons before his arrival.
"It was our fault we didn't qualify this year. We shouldn't have left it all to the last match when anything could happen."
Lazio, who have failed to win any of their last six league games, host Livorno on Sunday (1400) while fifth-placed Fiorentina are at home to Bologna.
Second-placed AS Roma, unbeaten after 15 games, visit AC Milan, the only Serie A team to survive the Champions League group stage, on Monday.