NAPLES, Italy -- Liverpool may consider losing 2-0 late on to Napoli in the Champions League at Stadio San Paolo as a good omen. After all, despite delivering their most deficient performance of last season in a 1-0 defeat here nearly a year ago, Jurgen Klopp's side went on to become Europe's best.

As was the case in 2018-19, Tuesday's trip to southern Italy represented the club's first away test on the continent. And while the arena and the opponents were the same, the manner of Liverpool's display was in stark contrast to the passive, blunt showing of 349 days ago. They were still on the wrong end of a 2-0 scoreline, which belied the design of a game that Carlo Ancelotti admitted the visitors nearly "took complete charge" of on Tuesday night.

Napoli's manager conceded that the two goals his side scored were from "curious circumstances." Dries Mertens got the first in the 82nd minute after a controversial penalty call when referee Felix Brych felt Andy Robertson had impeded Jose Callejon in the area. Replays showed that the Spaniard had dived and Klopp's assessment of the "gamechanging moment" that VAR did not overturn was in line with the footage. "When a player jumps before there is contact, then it cannot be a penalty," he said.

The second goal was born out of an uncharacteristic loose pass from Virgil van Dijk, with Fernando Llorente pouncing to double Napoli's advantage in added time.

Liverpool will be wondering how exactly they're returning to Merseyside with a 2-0 defeat after dictating large swathes of play. The hosts created more big chances but Klopp's men were wasteful when they did work openings. The front three of Mohamed Salah, Sadio Mane and Roberto Firmino were atypically laboured instead of illuminating.

"I felt we played some good stuff, it was just the final bit I felt we were missing today," said captain Jordan Henderson said in his post-match remarks. "At home, Napoli are a good side and they are going to create some good chances. You've got to be prepared to defend as a team, which I felt we did.

"We won some great balls in midfield and counter-attacked really well, but it was just that last little bit -- and obviously the mistakes for the goals -- that we need to improve on. Overall, we can be better of course. We'll take responsibility, we'll move forward and try to react in the right way."

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Klopp echoed the midfielder's evaluation. "I think we controlled the game in a lot of moments, we had a lot of interceptions, we won the ball and had counter-attacks," he said.

Both teams showed a lot of respect for each other, [were] very compact and defended well: that's how you play a game against a strong side, to be honest. The second half was a bit wilder, then we started to control the game again and then we conceded. You want to then have at least a point and we didn't get that because of the penalty.

"I think when you see the pictures it is clear that it wasn't. What can I say about it? It was very decisive in that moment for sure, but we cannot change it anymore."

There were several positives for Liverpool, chiefly Fabinho's performance which deserved to be on display in a museum as midfield art. His intelligent, well-timed interventions scuppered Napoli attacks before they became threatening and he instantly turned defence into offensive sequences for Liverpool.

No-one made more ball recoveries, tackles or passes than the 25-year-old. Fabinho was rivalled as his team's man of the match by goalkeeper Adrian, who served up his strongest showing for the club since deputising for the injured Alisson. He made a sharp double save to deny Fabian Ruiz early on before a strong right hand denied Mertens on the volley at the far post. It was goalkeeping of the highest standard, but Adrian's goal was still twice breached in a match that Klopp admitted was weird to analyse.

The big takeaway is that Liverpool's most exacting Group E test is now out of the way. Napoli are a more formidable proposition than they were last year when they also twice drew with Paris Saint-Germain the competition. In a mini pool that contains Genk and Red Bull Salzburg, the Italians are odd-ons to progress to the knockout round with the Anfield club, especially after Matchday 1.

While Liverpool have now lost four successive matches away from home at this stage in the Champions League, the defence of their European crown won't be dimmed by Tuesday's result. If anything, it will harden their desire to right these wrongs as was the case last season.

Chelsea, who suffered a surprising 1-0 defeat to Valencia in the tournament on Tuesday night, lie in wait at Stamford Bridge on Sunday. It's vital that the Reds shake off this rare setback and extend their unblemished Premier League streak and five-point gap on Manchester City at the weekend.