Liverpool suffered their first Champions League defeat of the season as Lorenzo Insigne's dramatic late winner gave Napoli the victory in their Champions League group game in Italy.
The hosts completely dominated the second period of the match with substitute Dries Mertens having an effort denied by the crossbar.
Goalkeeper Alisson Becker kept his Reds teammates in the contest until the end with the Brazilian ace denying efforts from Fabian Ruiz and Arkadiusz Milik.
Joe Gomez also had an encouraging game with the young Englishman clearing Jose Callejon's volley off the line.
It was a disappointing night for Jürgen Klopp and his players who failed to register a single shot on target in the match.
The Merseysiders could be accused of having too much attention drawn towards their mammoth clash with table-toppers Manchester City on the weekend as complacency certainly cost the Reds in Naples tonight.
Cagey first-half ends in a stalemate
A testing first-half for Klopp's Reds saw them pinned against a truly organised European heavyweight. Carlo Ancelotti's troops stuck to their gameplan to frustrate Liverpool to limited first-half chances.
Mohamed Salah was lurking when a backpass sent the ball to no man's land, with the Egyptian alert. David Ospina, though, was quickly off his line as he came to clear.
Naby Keita was withdrawn early on in the match as the former RB Leipzig midfielder left the field early on a stretcher before Reds captain Jordan Henderson was thrown in the deep end 19 minutes in to replace him.
The second period saw the hosts begin to find their rhythm and Liverpool looked a bit slow to track back when Napoli came forward and Milik found Insigne, who drove a low effort which flashed past the far post. Alisson might have just got there, but that was another warning for the Reds.
Some lovely build-up play again from Napoli also saw Insigne flick a smart pass back to Milik, who decided to shoot from range and Alisson got down low to save it.
Two chances in quick succession went begging for Napoli. Fabian failed to pull the trigger when he was sent through by Callejon. Milik also went close when his curled effort sailed wide.
Insigne steals it at the death
Napoli centre-back Kalidou Koulibaly surprisingly was seen sprinting down the left and crossed to the back post, where Callejon was left unmarked. The Spanish international sidefooted his effort towards the far post but Gomez heroically cleared off the line.
Substitute Mertens was introduced to the match as Ancelotti sent his Belgian forward on with the purpose of snatching a late victory and Mertens so nearly repaid his managers faith.
A superb delivery from Mario Rui was whipped across goal eluding every Liverpool defender in its tracks before it found the striker who struck the ball off his shin before it crashed against the bar.
The hosts must have thought their luck was running out; however, Napoli did deservedly steal it at the death when Callejon raced past Andrew Robertson down the right and delivered a perfect cross into the corridor of uncertainty.
Insigne was there unmarked in behind Trent Alexander-Arnold at the back post to slide home to set off an eruption of noise from the home fans.
It was a much-improved performance from Ancelotti's side following their disappointing 0-0 draw with Red Star Belgrade in their opening group match.
Alternatively, for Liverpool, it was a complete contrast of performance to the one that blew away PSG a fortnight ago at Anfield. However, all will be forgotten for Reds supporters should they get a positive result against the Citizens on the weekend.