Napoli can cause problems for Real Madrid if they take the game to them in Wednesday's Champions League clash at the Bernabeu, former Madrid coach Fabio Capello has said.
Napoli are unbeaten in 18 games but remain underdogs in the round-of-16 tie against the defending champions.
Capello told Radio Kiss Kiss Napoli that if the Serie A team used the ball intelligently they could make the home crowd anxious.
"Napoli must be very focused, not just in the first 15 minutes," the former England coach said. "They must not concede possession to Real Madrid.
"The Madrid fans are used to winning and seeing good football, so they can even whistle a bit if Napoli can play the ball out from the back.
"Napoli have the characteristics to make it difficult for Madrid, as they can play direct and first touch. That could create problems."
Capello said a key factor would be stopping full-backs Dani Carvajal and Marcelo.
"Carvajal and Marcelo play very freely and get forward, and they can cause problems in the opposition half," he added.
"Napoli must always try and push forward, never sit back. They must try and impose their game on the Bernabeu, although they are up against top level players. I wish them luck."
Brazil legend Zico also said he felt Napoli were capable of creating an upset -- as long as they did not let the occasion get to them.
Their forward line of Lorenzo Insigne, Dries Mertens and Jose Callejon have scored more goals combined this season -- 37 -- than Real's Cristiano Ronaldo, Karim Benzema and Lucas Vazquez, who have 36.
"I've seen Napoli play a few times and you can see they have a good coach by how well they play," the 63-year-old told La Gazzetta dello Sport.
"I'd say that they can cause quite an upset and cause Real Madrid problems with their pace. The important thing is that they don't have any fear, because that stadium can get to you.
"Then they need to ensure they don't leave any room to that phenomenal player Cristiano Ronaldo. If you lose sight of him, you're doomed -- he punishes you immediately."
Information from ESPN FC's Italy correspondent Ben Gladwell was used in this report.