1 Villas-Boas is really not one to sit on the fence

Gut instinct suggested André Villas-Boas's team selection bordered on professional suicide. Having lost John Terry early in the day with an exploratory arthroscopy on his knee to come, he chose to start without Frank Lampard – a player not at the height of his powers but the most experienced midfielder available – and Michael Essien. Ashley Cole was deemed fit enough to come on early having initially been left out for José Bosingwa, the manager having therefore initially asked an inconsistent right-back to fill in on the opposite flank. The risks to dressing room harmony were obvious. Yet Villas-Boas has admitted some of the players are not buying into his approach. In that context he could point to this team and claim that, if his tenure was to unravel, then at least he would be going down with players who were with him.

2 The selection was bold but the team still felt error prone

As it was, for all the tantalising promise offered by Juan Mata's opening goal and the initial ruggedness of their defending, any combination flung down by the manager retains an air of vulnerability these days. Cole, when introduced for the hamstrung Bosingwa, was outpaced too easily by Christian Maggio at times. Branislav Ivanovic, initially impressive, endured one lapse and was punished by Edinson Cavani in first-half stoppage-time. Raul Meireles, a poor imitation of a midfield shield, lost Ezequiel Lavezzi for Napoli's opener and might have handed the Italians another goal early in the second half. Lapses of concentration so blatant tend to cost ties at the knock-out stage of this competition.

3 The Italians' attacking threat is slick and streetwise

This Italian club's rise from the third tier of their domestic game to the last 16 of the Champions League within eight years is staggering enough but the attacking bite they displayed here indicates just how they have cantered back to prominence. Cavani, Lavezzi and Marek Hamsik purr at times even if the last was quiet for periods. Cavani's presence alone must strike fear into opponents – there is something of Didier Drogba's strut in his play – while Lavezzi's movement and vision take the breath away. His curled conversion was superbly taken, though Maggio's industry and incision on the flank and the busy Walter Gargano were just as eye-catching. Better defences than Chelsea's will be troubled by the pace and quality with which this team tears at them.

4 The Premier League has been taught a lesson

The week endured by Arsenal and Chelsea in this competition, as well as the failures of both Manchester clubs to emerge even from their groups before Christmas, has provided an indication of the relative mediocrity at the top of the Premier League. Both London sides would have expected to progress in recent seasons. Both now feel scorched by brushes with Serie A. For Chelsea this was a real eye-opener. Drogba had said on the eve of this match that this team tends to rally at moments of crisis. Those days appear to have gone. While Manchester City may still be evolving into a real force, United, Chelsea and Arsenal feel transitional and, as a result, peripheral when it comes to European football at present.

5 Napoli are certainly not unbeatable

In truth it is hard to imagine either of these sides challenging for the trophy itself. Napoli, for all their sparkle in attack, appear fragile at the back, which is reason enough for Chelsea to retain some level of optimism for the return. The hosts' three-man defence is not the most mobile and a team with pace and invention might rip them to shreds. How the Londoners must crave the ability to whip up a feverish opening to a contest, as they did so memorably against Barcelona back in the 2009 semi-final. The Italians might just wilt under such a barrage. Yet times have changed and the current side too often seem stodgy where once they flew at rivals and blew them away. There lies a real source of frustration.