Injuries no excuse against Napoli: Barca coach Xavi
The Catalans are aiming to reach the quarter-finals of the competition they last won in 2015, with the tie level at 1-1 after the first leg in Italy.
Xavi is missing three key midfielders in Pedri, Gavi and Frenkie de Jong, as well as Ferran Torres and Alejandro Balde.
However the coach said his team could not use that as mitigation for failure and demanded a "magic night" at the club's temporary Olympic Stadium home on the city's Montjuic hill.
"It's the moment to be able to reach the quarter-finals, for four years we haven't got to the last eight of the Champions League, I see it as an opportunity," said the coach.
"It's true that we have players out, but it's not an excuse. It's an opportunity."
The coach announced in January that he would leave Barcelona at the end of the season, and the Champions League is a final chance to go out on a high.
Despite leading Barcelona to the Spanish title last season, Barca are off the pace in third in La Liga, out of the Copa del Rey and were thrashed by Real Madrid in the Spanish Super Cup.
"I am not the important thing here, the club is the important thing -- I have an expiry date," continued Xavi.
"With Barcelona united, with the stadium full, we have to live a magic night."
Xavi said there were no favourites in the tie and that he thought it was "50-50", although home advantage could tilt the match Barcelona's way.
"It has to be a pressure cooker," added Xavi.
"The players have to feel the support of the fans."
The team have struggled badly in defence for the majority of the season but have now kept three clean sheets in a row.
Young centre-back Pau Cubarsi, 17, has become a fixture in defence for Xavi and could start against Napoli.
"We all hope he continues like this," said Barcelona goalkeeper Marc-Andre ter Stegen.
"Imagine how much he can improve still, it's time for him to keep racking up the minutes ... he's in spectacular form and we have to take advantage of it."
Another change Xavi has made in recent weeks is using defender Andreas Christensen in defensive midfield.
"Now there is a good balance between the lines," added Ter Stegen.
"With Andreas as a pivot we are more balanced in defence and attack, he gives us a lot and I'm happy for him -- he's calm and confident."