The Italian side host Swansea at the Stadio San Paolo with all to play for, having been held to a goalless draw in the first leg in Wales last week.
"We want to progress and in order to do that, we need to score more goals than they do and win," Benitez said in Wednesday's press conference. "This is a crucial game for us.
"We are confident because we can do good things this season."
Benitez is aware his players will have to play better than they did in the first leg at the Liberty Stadium.
"We already saw that Swansea play great football," he said. "We have to play as we know how, but we must increase the tempo."
Napoli are third in Serie A and are considered firm favourites to progress. However, Benitez is not taking the Swans lightly.
"I know Swansea well," he said. "They did a great job against us as well as against Liverpool at the weekend.
"They scored three goals against the Reds, but they also conceded four.
"They have a team capable of progressing to the next round of the Europa League.
"We have to be ready, we need to be clinical in attack and strong in defence.
"We need to impose our game."
Napoli, who were only eliminated from this season's Champions League group stage on goal difference, were held to a 1-1 home draw by Genoa on Monday in Serie A.
However, Benitez does not believe tiredness will be a factor for his side.
"I don't see a problem in terms of my team's condition," he said. "I think the key will be to control better our emotions than with respect to the first leg."
Napoli will be without goalkeeper Rafael, who tore the anterior cruciate ligament in his right knee against Swansea and underwent surgery this week in Brazil.
Jose Reina, who is on a season-long loan at Napoli from Liverpool, will deputise between the posts, and the Spain international is relishing the challenge.
"We want to do well in the Europa League," he said. "We know it's going to be a complicated game because Swansea play well.
"But in the big games we have always done well.
"The Premier League is very competitive and teams that are in mid-table play very good football.
"But we are determined to progress.
"Once you get to the quarter-finals of the European competitions, every team wants to win the trophy.
"I've had the fortune of playing in a lot of European games, and these type of games are always special."