When Maurizio Sarri’s side are on form, they play some of the best football in Europe, writes Gaby McKay .

During the first half of their win over Milan last week, Napoli were quite simply brilliant. Lorenzo Insigne and Jose Callejon put Maurizio Sarri’s men 2-0 up after just 10 minutes, and could have been four goals to the good before Juraj Kucka got one back for the home side.

The match was live on television around the world, and there could not have been a better advert for Serie A - not just in terms of the pulsating match, but in the football played by the Partenopei. When Sarri’s boys are on song, they play the best football in Italy, and arguably the best in Europe.

Barcelona, Arsenal and Monaco can all be astonishing when on top form, but Napoli’s best football easily stands up to comparison with those clubs. In Insigne, Callejon, Dries Mertens and Marek Hamsik, the Neapolitans have a vibrant, skilful attack, with Jorginho and Allan giving them a platform to play.

Despite losing last season’s top-scorer Gonzalo Higuain in the summer, the Partenopei have scored 47 goals in 21 games this season, as well as banging in 11 in their six Champions League games so far.

Napoli were not rewarded for topping that group and will face Real Madrid in the Last 16. They will not be lambs to the slaughter when they take on the reigning European champions, however. Roma showed last season that Zinedine Zidane’s men are vulnerable at the back, and could have knocked them out in the Last 16 were it not for the wayward finishing of Mohamed Salah and Edin Dzeko.

If Napoli can stop Cristiano Ronaldo at the other end - no easy task, granted - then they are as unlikely to be as profligate as the Giallorossi. If the Italians are on-song, we could be in for a real classic across the two legs, with the Stadio San Paolo sure to be bouncing for the return.

Unfortunately, that is the caveat. When the Partenopei are in top-form they’re irresistible, but if the machine isn’t quite oiled properly, they can struggle. Having dominated Milan in the first half at San Siro, they risked allowing the Rossoneri back into the game. Sarri’s men should have been out of sight, but were forced to endure a nervy finish as the Diavolo pushed for an equaliser.

Juventus may not be as stylish as Napoli, but the Bianconeri tend to find a way to win when they aren’t playing well. Their Neapolitan challengers have improved in that regard this season, but have still dropped points with Pescara, Atalanta and Sassuolo.

That said, a summer of changes and the loss of their star player was always going to require some adjustment, and an in-form Napoli are a match for any side in Italy and in Europe.

If the free-flowing, exciting Partenopei show up against Madrid, and when Juventus visit the San Paolo in April, there is no limit to their ambition.