As Chelsea prepare for the first leg of their Champions League clash with Napoli at San Paolo on Tuesday evening, it’s tempting to recall how André Villas-Boas spent a season in Serie A scouting opponents for Inter Milan as an assistant to José Mourinho.


Italian football is far from unfamiliar territory to the Chelsea manager. He knows its teams, coaches and players, and won’t be under any illusion as to the threat Napoli pose.  “We have one of the most difficult draws,” Villas-Boas said in December.


Napoli’s rise has been one of the major talking points of this season’s Champions League. Re-founded following bankruptcy in 2004, it’s nothing short of remarkable that in the space of seven and a half years, they have gone from Italy’s third division to the last 16 of the Champions League.


The club’s reputation as football’s equivalent of Lazarus was only enhanced by their emergence along with Bayern Munich from the so-called Group of Death, which also included Premier League leaders Manchester City and Villarreal. It’s without precedent in Italy. No team has come so far so quickly.


Searching for a comparison, La Gazzetta dello Sport could only think of one better: Brian Clough’s Nottingham Forest, who earned promotion to the top flight in 1977, won the old first division in 1978 then lifted the European Cup in consecutive years in 1979 and 1980.


The pink paper has since revised its opinion finding more in common with Rafael Benítez’s Liverpool in 2005. They came a modest fifth in the Premier League, but still reached the Champions League final in Istanbul and came from 3-0 down to overcome AC Milan against all odds.


Chelsea supporters remain haunted by that year. They were eliminated by Liverpool in the semi-finals after Luis Garcia’s controversial “ghost goal” in the second leg at Anfield. Whether it crossed the line or not is still subject to fierce debate today.


Up until now, Walter Mazzarri’s Napoli have followed a similar pattern to that Liverpool side. When the spotlight is on, they have risen to the big occasions, tasting victory over City, Milan and Inter, as well as drawing with Bayern Munich and Juventus. The impression is that they can beat anyone on their day.


Getting up for the smaller teams has, however, proven a problem. Tipped for the title after spending £37.2m on a team that finished third last season, defeats to Chievo, Parma and Catania plus the draws they’ve been held to by Novara, Bologna, Siena and Cesena have seen them fall out of contention.


How can this be explained?


“It happens to everyone in their first year in the Champions League,” Napoli and Chelsea legend Gianfranco Zola explained.  “It was like that for me at Chelsea [in the 1999-00 season when the team’s league form suffered as they reached the Champions League quarter-finals only to be eliminated 6-4 on aggregate by Barcelona]. Being on display in Europe is too exciting. You burn too much nervous energy.”


That’s certainly true of Napoli. Between mid-January and early February, they went through a five-game slump without a win in Serie A. Yet as their encounter with Chelsea has edged closer and closer on the horizon, the adrenaline has started to pump through their veins again.


Friday night’s 3-0 victory at Fiorentina was their second-in-a-row. It moved Napoli up to sixth place in Serie A and served as a reminder to Chelsea of what this team are capable of when they are on top form. Their ‘Three Tenors’ up front, Edinson Cavani, Ezequiel Lavezzi and Marek Hamsik were all on song.

Cavani scored his 21st and 22nd goals of the season, converting an assist from Hamsik, while Lavezzi ran the length of the pitch in the 91st minute to get himself on the scoresheet. Napoli’s defence also went unbeaten for the fourth consecutive game in the league.


“The first thing that comes to mind after this great performance is that we can finally think about the match against Chelsea, which we have been waiting for forever,” Cavani told reporters.


One gets the feeling Napoli have been counting down the days until Chelsea’s visit to the San Paolo. The Champions League has been a priority this season. Twenty-two years after last playing in this competition’s predecessor, they’re savouring every moment of it and don’t want it to end.


Napoli’s unorthodox 3-4-2-1 formation and their fast-break counter-attacking style will ask questions of Chelsea whose penchant for defending with a high line plays right into their opponents hands. Villas-Boas can ill-afford to get this tie wrong.


Speaking after Saturday’s 1-1 draw with Birmingham City in the FA Cup fifth round, when he was forced to deny “ridiculous” claims Didier Drogba had given a team talk in the tunnel at half-time, Villas-Boas said he had the “unconditional” support of Chelsea owner Roman Abramovich despite a run of four games without a win.


Tuesday night’s result against Napoli might still prove decisive for his future. Lose and he could be out. “If he leaves Chelsea, he’ll be the next coach of Inter Milan,” Villas-Boas’s former boss, Porto president Pinto da Costa told La Gazzetta dello Sport last week.


While that would mean he’d have come full circle, let’s not jump to conclusions. Villas-Boas won’t be treating this as an audition, but rather as another appraisal of his work so far at Chelsea and passing a test like Napoli won’t be easy.


This piece first appeared for BBC Sport