Having already guided SSC Napoli past one English team in their debut UEFA Champions League group stage campaign, coach Walter Mazzarri acknowledged that his side will have to raise their game if they are to account for another in the shape of round of 16 opponents Chelsea FC.

Though Napoli have never met the west Londoners in UEFA competition, their Group A experiences against Manchester City FC − a 1-1 away draw and 2-1 victory at the Stadio San Paolo − should stand them in good stead to face the 2008 runners-up.

Mazzarri, whose charges are at home in the first leg on 21 February, expects the return encounter at Stamford Bridge on 14 March to be pivotal, saying his players will have to deliver a "perfect" display if they are to continue their impressive first season among the continent's elite.

"Chelsea are one of the best teams in Europe – there's no doubt about that – and after a period of crisis they are back on top form thanks to the performance of a great player like [Didier] Drogba," said Mazzarri, alluding to a run of three successive victories for André Villas-Boas's team.

"In their last league game, they defeated Manchester City [2-1], who were dominating the Premier League until then. That says everything about Chelsea's strength. We have the first leg at home, but the return at Stamford Bridge will be decisive in terms of qualification. We will have to be perfect in London if we want to get through, that's for sure."

Chelsea manager Villas-Boas said that Napoli were one of the toughest teams in the draw. "Napoli is a club that represents the city and the city has great empathy with the club," explained the Portuguese. "It has a tremendous fan base and it is one of the most difficult and exciting games of the last 16, no doubt about it."

"They are a side that work collectively very well and Walter Mazzarri has always been a coach that organises his teams very well," added Villas-Boas, who went on to cite Napoli's attacking threat. "They are fully motivated and they have a lot of talent coming through, like [Marek] Hamšík and [Edinson] Cavani."