Liverpool's Champions League campaign got off to a nightmare start in hot and humid Naples on Wednesday as sensational Napoli ran out comprehensive 4-1 winners.

Victor Osimhen set the precedent early on, hitting the post inside the opening 60 seconds before James Milner clumsily conceded a fifth-minute penalty, which Piotr Zielinski kept his cool to convert.

Liverpool, stunned into submission, then presented Osimhen with his own chance to test Alisson from 12 yards after an ill-timed challenge from Virgil van Dijk was penalised by VAR review.

Alisson denied the Napoli striker's spot-kick attempt, but Liverpool's reprieve only lasted 13 minutes. Khvicha Kvaratskhelia outmuscled Joe Gomez, who endured a torrid 45 minutes before being hauled off, to present Andre-Frank Zambo Anguissa with an opportunity to slot the ball low past Liverpool's helpless 'keeper.

Things went from bad to worse shortly before the interval as substitute Giovanni Simeone - on in place of the injured Osimhen - was found unmarked in the six yard box to turn home Kvaratskhelia's pinpoint cross.

Zielinski rounded off the scoring for Luciano Spalletti's new-look side two minutes into the second period to compound Liverpool's misery, before Luis Diaz temporarily quietened the deafening home crowd when cutting inside to bend a low right-footed shot beyond Alex Meret.

Diaz, Liverpool's only saviour on an otherwise sultry evening, also saw a thumping header saved while concerns in midfield personnel were slightly assuaged by the reemergence of Thiago and debut of Juventus loanee Arthur - both second-half substitutes.