Dries Mertens’ penalty and a late Fernando Llorente goal condemned Liverpool to defeat in their Group E Champions League opener against Napoli.
Belgian forward Mertens scored from the penalty spot after Liverpool defender Andy Robertson was judged to have fouled Jose Callejon.
Former Tottenham forward Llorente then capitalised on a mistake from Virgil van Dijk in stoppage-time to roll the ball past Liverpool keeper Adrian.
Jurgen Klopp’s side are the first winners of the competition to lose the opening game of the following campaign since AC Milan in 1994.
Goalkeeper Adrian had earlier made two keys saves for Liverpool, who initially struggled to impose themselves in the intimidating atmosphere of the San Paolo Stadium.