Late goals from Dries Mertens and Fernando Llorente earned Napoli a 2-0 victory as Liverpool made a slow start to their Champions League defence
For the second season in a row, Jurgen Klopp's side were beaten in the group stage in Naples - they lost 1-0 last October - and it was more sloppy defending which saw the Group E game slip away from them in the final minutes
The Reds had defended stoutly against some sustained pressure from the home side, but were unlucky to be punished when Jose Callejon skipped inside of Andy Robertson before making the most of minimal contact with the Liverpool defender and, when a VAR review failed to give the visitors a reprieve, Dries Mertens took full advantage to beat Adrian from the spot
"For me it's clear and obvious, no penalty, because Callejon jumps before he has any contact," 
As Liverpool pushed for a late equaliser, Fernando Llorente doubled the lead during added-on time after a rare Virgil van Dijk mistake, profiting when the defender's mis-hit pass ran into his path and he slotted the ball home to spark wild celebrations on the home bench
Victory was sealed - and the reigning champions of Europe had been beaten in the first game of their defence for the first time since AC Milan in 1994
Liverpool were hoping for better than their limp showing at the Stadio San Paolo last season, but found themselves caught out on the break early on when, as they would have feared, Lorenzo Insigne found space in behind Trent Alexander-Arnold
 But from his pull-back Fabian twice pulled simple saves out of Adrian from a good position
Liverpool responded when Jordan Henderson's lob found Sadio Mane unmarked on the edge of the box, but his heavy touch took him wide of Alex Meret's post and, from a tight angle, it was simple enough for the goalkeeper to turn his effort round the post with his legs
There was little more to shout about from either side before the break although it took a last-gasp challenge from Alexander-Arnold to take the ball off Insigne's foot as he prepared to shoot
The second half did not take so long to liven up
 It was less than four minutes old when Liverpool were indebted to a world-class save from Adrian to stay level, with the goalkeeper somehow tipping over Mertens' far-post header when he looked certain to score
When the visitors did get chances to attack, their front three looked out of sorts; it was summed up when Mane hung onto the ball too long as Liverpool broke before over-hitting a simple pass across to the unmarked Mo Salah
Liverpool were left to rue those misfiring attacks when Callejon took a late tumble under pressure from Robertson, the referee pointed straight to the spot and Mertens found the bottom corner, despite a commendable effort from Adrian
It was already looking like a case of deja vu for Liverpool at this point, but things got worse in added time when Van Dijk's uncharacteristic error set up Llorente, who had been in the defeated Spurs squad in last season's final, to slot under Adrian and seal three points for the hosts
"It was comfortable, they created chances, I think they had four on target which was an improvement from last season when they only had one
 But it wasn't a typical Liverpool performance; we didn't see Andy Robertson or Trent Alexander-Arnold bombing forward
"Sadio Mane looked sharp, Mo Salah looked sharp at times, they did create chances but it was a masterclass from Kalidou Koulibaly - he was like the Virgil van Dijk of last season, and Liverpool got no joy out of him
 It was a couple of sucker-punches
"After that Adrian save, you thought 'yeah, coming out of this 0-0, it's a good point', but unfortunately they lost it
"Chelsea host league leaders Liverpool on Renault Super Sunday - live at 4pm on Sky Sports Premier League; Kick-off 4
30pm
The Reds' next Champions League game is at home to Red Bull Salzburg, who thrashed Genk 6-2 in their opening game, on October 2
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