Going into the final 10 minutes at Stadio San Paolo, Liverpool fans would have been justified in wondering whether their side might choose to simply hold out for a decent point.
Napoli's ambition had been somewhat stunted by the withdrawal of Lorenzo Insigne and Hirving Lozano, the pair's pace having been a crucial factor in their ability to break out quickly.
The Reds, meanwhile, were enjoying most of the ball and looked to the majority of observers to be the team most likely to break the deadlock - should they elect to go for the jugular, of course.
Then, Andy Robertson dangled out a leg for Jose Callejon and Virgil van Dijk seemed to forget where he was, consigning the visitors to defeat in Naples for the second consecutive season in the process.
It felt like less than Liverpool deserved given what they had put into the game, but then that is the nature of football at this elite European level.
As reigning champions of this competition, perhaps Jurgen Klopp's team should know that better than anyone.
European blow far from fatal
Victory over the group's second seeds here would have put Liverpool on track to secure a place in the Champions League knockout stages with two games to spare.
Now, however, they face a battle to go through as group winners - an outcome that would, in theory, secure an easier tie in the next round.
That is not a disappointment they can afford to dwell on too long, though, with three winnable group games following this testing trip to Naples.
The Reds will fancy themselves to beat RB Salzburg at Anfield before doing the same to Genk home and away, and that combination of results will put them in touching distance of qualification.
Klopp's side know they have it in their hands still.
Reds performance shows strides made
Klopp often talks about the fact that only good performances can guarantee good results in the long term, and that the controlling the former is far easier than the latter.
As such, he will have spent the build-up to this game not simply hoping that his side came away with a better outcome, but doing all he could to ensure an improvement on their Stadio San Paolo showing.
In the aftermath of yet another defeat in Naples, it would be easy to say that Liverpool did not deliver on that specific target for the game, but that would be completely unfair.
He won't be happy having lost, but Klopp will take pleasure from plenty of elements of the Reds' performance, which showed they are a far better team than at this stage of last season.
Opportunities to prove that continue to come thick and fast, with a visit to Chelsea up next.
Fabinho shows off flexibility
If Fabinho's imperious Newcastle performance proved his worth against the so-called 'lesser' sides, then tonight was all about underlining his value in the biggest of fixtures.
The Brazilian spent Saturday afternoon keeping the Magpies penned in their own half, ensuring a Liverpool goal became an inevitability following wave after wave of attack.
Here, however, he was tasked with keeping the Reds solid and smart in the centre of the park against an infinitely more ambitious opponent.
The six tackles, 62 passes, and one interception he made across 90 minutes are a testament to just how good a job he did of that, even if the result wasn't the right one.
These days, Fabinho is truly Klopp's man for all seasons.
Van Dijk gets rare error out of his system
Van Dijk doesn't often make mistakes, so perhaps it was worth him getting this one out of his system in a game that was heading for defeat anyway.
The Dutchman had been a rock at the back all night, consistently repelling dangerous crosses, particularly from Napoli corners that had been designed to tee up Kalidou Koulibaly.
It is those sorts of contributions that have characterised his time at Liverpool rather than the horrendous error that teed up Fernando Llorente.
Fortunately, Van Dijk is not the sort of character to carry that sort of moment with him into the next game unless it is as motivation to put things immediately right.
