Ivan Campo believes Napoli can make life difficult for Real Madrid when his former club face the famously hostile Stadio San Paolo atmosphere in the last 16 of the Champions League.
Madrid welcome their Serie A opponents to Santiago Bernabeu for the first leg on Wednesday and must negotiate a trip to Italy next month.
The sides met in a memorable European Cup tie in 1987, with Emilio Butragueno inspiring Madrid to victory over Diego Maradona's Napoli over the course of two contrasting games - the Bernabeu leg was played out before empty stands as a punishment for crowd trouble during Madrid's semi-final with Bayern Munich the previous year, while a raucous San Paolo crowd were unable to prevent their side slipping to a 3-1 aggregate loss
Maradona's time in Naples remains a high-watermark for the club, but Campo is also impressed by the current generation under Maurizio Sarri, who he expects to test Zinedine Zidane's men.
"Well, even though people may think it will be easy for Real Madrid, Napoli are in the last-16 round for a reason," Campo, was on the books at Madrid between 1998 and 2003, told Omnisport.
"They are a good side. The atmosphere they will have at their stadium will be unbelievable.
"Everyone knows Maradona played there once and the atmosphere they have been living at their games for years is truly amazing.
"It won't be easy for Real Madrid. Nevermind how easy it may seem, for Napoli fans that won't be the case.
"If we think this will be an easy one we will struggle."