Italian legend Fabio Cannavaro feels Napoli must score at Chelsea to be sure of winning their Champions League tie.

The Azzurri beat the Premiership outfit 3-1 at the Stadio San Paolo on Tuesday, but the former Italian international insists qualification is not yet secure.

"The return leg at Stamford Bridge won't be easy," the former Napoli, Parma, Inter, Juventus and Real Madrid man claimed.

"There will be a hot environment and they'll need to take a step up in quality to defend their advantage, as their lead may not be enough.

"They'll have to score at least one goal against the Blues."