The Partenopei brought in three new faces before the window closed this week - Brazilians Henrique and Jorginho, along with Algeria ful- back Faouzi Ghoulam - in an effort to bolster their Serie A campaign.
Speaking ahead of his side's game against Atalanta on Sunday, Benitez suggested that a younger, more balanced team would ultimately pay dividends in the club's pursuit of silverware.
"I'm really satisfied with our transfer market activity," the 53-year-old Spaniard told a press conference.
"We managed to lower our average age and now the squad is more compact and balanced. Next we will need reveal our evolution on the pitch.
"We have managed to secure the services of three new players we felt we needed in the team. Jorginho, Henrique and Ghoulam are elements added to our new squad, which complete and fulfil our needs. They have chosen to grow in quality and potential and we are working with them to offer more to the team. We have invested in these new acquisitions to earn success."
January also saw Paolo Cannavaro - who has made just four appearances under Benitez this season - join Sassuolo on loan for the rest of the season, and the Spaniard wished the experienced defender well with the move.
"I would like to wish all the luck in the world to Paolo Cannavaro in this new phase of his career," Benitez said of the 32-year-old..
"He is a great person, a player with great professionalism and a man who has been very important for this club. But that's football and these things happen. We wish him all the best on the path he has taken outside Napoli."
Napoli, who sit third in Serie A with 44 points from 21 games, face Atalanta on Sunday as they look to close the 12-point gap to leaders Juventus.