Napoli 2-0 Liverpool: The Warm Down
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Liverpool began their UEFA Champions League campaign with defeat as they were beaten by Napoli 2-0 at Stadio San Paolo on Tuesday evening.

The reigning champions conceded a controversial penalty in the 80th minute when Jose Callejon went to ground inside the Liverpool box - Dries Mertens subsequently converting the spot kick.

In the final minutes of the encounter a rare error from Virgil van Dijk put Fernando Llorente through on goal who scored the second and final goal of the night.

Here are some of the key talking points from a disappointing night in Naples.

VAR called into question yet again

A tense, tough affair in Italy was tarnished by the controversial Video Assistant Referee which essentially gifted Gli Azzuri three points, leaving the Reds empty handed and frustrated.

With the game deadlocked with 10 minutes to go Callejon made his way into the visitor's box with the ball at his feet, going to ground after Andy Robertson closed the Spaniard down.

At first glance it seemed as if referee Felix Brych had made the right decision by pointing to the spot, but the following replays identified the intentions of the 32-year-old winger, going to ground before any proper contact was made by Robertson.

With cameras clearly picking up the incident, and with VAR in use, it was expected that Brych’s decision would be overruled. Instead it was not deemed a clear and obvious error to review. The penalty went ahead, which Mertens would go on to score, much to the dismay of the travelling Reds.

So what is the point in VAR?

In one of, if not the biggest club competition in the world, in arguably the biggest fixture of the group, tied at nil-nil with only a matter of minutes to play, surely a scenario like this would have to be reviewed to clear up any controversy that could come from it?

There will be varying judgements from fans as to whether it was right to grant the penalty or not, but isn't that why it was brought into the game? Right now the current state of VAR is as complex as it is disputable, clouding judgement whilst becoming the main talking point of the fixtures that are unfortunate enough to be scarred by its errors.

Fortunately for the Reds there is five remaining games in Group F to qualify for the knockout stages, something that is anticipated of them in their pursuit to retain the Champions League. However if this fixture was Liverpool's last roll of the dice to proceed to the last 16, we could be in the midst of a bitter storm regarding the use of the technology.

'Anti-Liverpool' tactics pay off for Ancelotti

Focusing on the game, Napoli found great success in their defensive tactics, suppressing the notoriously clinical front three of Sadio Mane, Roberto Firmino and Mo Salah.

The Reds are familiar with the calibre of Carlo Ancelotti's side, especially at Stadio San Paolo. A tough visit to Italy last year saw Liverpool limited for chances, losing 1-0 after Napoli captain Lorenzo Insigne scored a last minute winner.

The quality of the Serie A side does not stop with their skipper. Kalidou Koulibaly is widely regarded as one of the world's top centre-backs, whilst Mertens, Insigne and new additions such as Hirving Lozano and Kostas Manolas have strengthened an already powerful European outfit.

The pairing of Koulibaly and Manolas made life hard for Liverpool's front three, who were isolated for portions of the game. Ancelotti's low block provided the home side with a defensive overload, making it difficult for the likes of Jordan Henderson and James Milner in midfield to win the ball in high up in Napoli's half.

It even secluded the usually offensively spirited full backs Robertson and Trent Alexander-Arnold, who found their chances in the final third limited throughout the game.

That being said, Jurgen Klopp's men did create a few notable chances throughout the match, and if it wasn't for the heroics of goalkeeping prospect Alex Meret from Salah's vicious effort 65 minutes in, the away side could have took the lead with half an hour to play.

The game ultimately ended in defeat and disappointment no thanks to the tactics of Ancelotti, but the Reds can take a few positives back home in a game that could have gone either way.

Fabinho was one of the most impressive players on the night, the Brazilian continuing his stellar start to the season with a dominant display in the middle of the park.

It’s also worth mentioning that Adrian was impressive on his Champions League debut - a double save in the first half and a superb stop from a powerful close range volley from Mertens the highlights for the Spanish ‘keeper.

Reds can't afford to lose optimism

Klopp and his side played their first of four away games in 11 days last night, and now cannot afford to drop their heads as a fiery encounter with Chelsea at Stamford Bridge is right around the corner.

The Blues themselves fell short last night in the Champions League, losing 1-0 at home to Valencia.

The loss will halt Frank Lampard's growing momentum with his youthful side, something that Liverpool will have to take advantage of come Sunday evening as they look to maintain their flawless start to their league campaign.

The red half of Merseyside will be confident in their club's ability to respond to last night's loss, and with a win against Chelsea potentially extending their lead at the top of the Premier League to eight points (based on the outcome of other results), Klopp's men will have noted the importance of a win in London.