The room was hot and airless by the time André Villas-Boas took his seat, deep in the bowels of the Stadio San Paolo, and did his level best to assure us that this time it was different and we could take his word for it that Roman Abramovich was no longer guilty of the short-termism we have seen so many times before.

He did not just talk about surviving the Champions League tie against Napoli but spoke of his belief, more than once, that it would be a more cohesive Chelsea under his management next season and reiterated, more decisively than at any time over these difficult past weeks, that he had been guaranteed his job was safe whatever happens inside this vast, chaotic stadium.

He understood the scrutiny, he said, given the "cultural past of this club", which felt like a polite way of describing Abramovich's habit of moving on managers who come up even slightly short of what he wants. He said he had "the total confidence of the owner" and there were only the briefest flashes of irritation when the questions went on a little too long for his liking. Otherwise Villas-Boas held eye contact, talked with self-assurance and there was never any sense of a man floundering for oxygen. If he does suspect he is one more bad result from becoming another Abramovich statistic, he made a pretty good job of disguising it.

Whether he is entitled to be so optimistic is open for debate when the one thing we know about Abramovich by now is that men with his wealth and power run short of tolerance.

Abramovich has already told the players Villas-Boas will be there for at least two more seasons and perhaps it is true that the Russian has come to understand that Chelsea need some continuity. Equally one cannot ignore Abramovich's history of hiring and firing – not when Villas-Boas's side have won only two of their 10 league fixtures since beating Manchester City on 12 December, the result that was meant to reinvigorate their season.

A team who were supposed to challenge for the league have dropped to fifth, 17 points off the top, and the culture of leaks at Stamford Bridge has brought into the open the dislocated relationship between the manager and players.

Villas-Boas also had to contend with stories in the Spanish press claiming that Abramovich's representatives have sounded out Marcelo Bielsa, the former Argentina coach who moved on to Chile, winning 42 out of his 76 games, and now manages Athletic Bilbao, currently lying fifth in La Liga.

Even if Abramovich does spare Villas-Boas, these are the kind of stories that will attach themselves to Chelsea for as long as the team are floundering.

The only way to remedy that, as Villas-Boas pointed out, is to return to the business of winning matches but Napoli are formidable opponents in the concrete, graffiti-covered San Paolo, even if their sixth position in Serie A, 13 points off Milan, indicates they are not perhaps as accomplished as has sometimes been made out since knocking out City at the group stages. The din inside this antiquated stadium is as raucous as anywhere in Italy – Che Siano novanta minuti di fuoco ("It will be 90 minutes of fire") declared one banner when City lost here in November – but too much can sometimes be made of a crowd's noise. Walter Mazzarri's team have won only nine out of 24 league fixtures this season.

"Whatever happens will not be decisive," Villas-Boas said. "We have to remember that this is the first leg and Stamford Bridge is a great stadium for European nights, too. But we have to be conscious of Napoli's strengths at the San Paolo, which can be amazing. This a team that has been built up with Europa League qualification last year and now have done very well in the Champions League."

These are the moments when the Chelsea players need to put aside the politics and whatever mutinous thoughts they might have against their manager.

In short, they need to "man up", to borrow the phrase John Terry used before they played Copenhagen after a bad run at this stage last year. The alternative, for Villas-Boas, might be hardly worth thinking about.