NAPLES • Jurgen Klopp has claimed Liverpool were undone by a dive and that the video assistant referee (VAR) remains at the mercy of human error after their Champions League defence started with 2-0 defeat by Napoli on Tuesday.
The loss also means that the Reds are the first title-holders to lose their opener since AC Milan in 1994.
Andy Robertson was adjudged to have fouled Jose Callejon for the 82nd-minute penalty that turned an open contest in Napoli's favour at the Stadio San Paolo.
Dries Mertens converted the spot kick and an uncharacteristic mistake from Virgil van Dijk enabled Fernando Llorente to seal victory in the final seconds.
Referee Andy Felix Brych's decision to award a penalty against Robertson was not deemed a clear and obvious error by VAR, however, leaving Klopp to lament the regulations.
"I'm pretty sure there are different views on that situation," the Liverpool manager said of the decision. "But when the player jumps before there is contact, then there cannot be a penalty.
"That was the game changer. It was very decisive in the moment. I could say a lot of things about it but I'm not a bad loser. I'm not the best loser, but I'm not bad."
As for VAR's involvement, Klopp added: "It's a decision made by human beings. The rules say if it is not a clear mistake and it's still humans who decide if it's a mistake.
"It (VAR) will help in the long term but as long as human beings make the decision, there is still potential for failure.
"We are all like this. What can I say? The rules are like this, and they'd have to adjust the rules.
"The German (refereeing) team, they do it for a while already, the VAR was also German, they have been using it longer than others.
"They will find an explanation about why they did the right thing, that's how it is. If he didn't whistle for the penalty, he wouldn't have been overruled by VAR.
"We all wanted to have more clarification in these things, now we don't have it."
Liverpool, however, are still heavily fancied to progress from Group E despite Red Bull Salzburg's emphatic 6-2 win over Belgian outfit Genk. Klopp insisted his players would "change the table" in the next few games, with the Austrian side due to visit Anfield on Oct 2.
When asked about the VAR controversy, Napoli coach Carlo Ancelotti refused to be drawn into the debate, instead preferring to praise the hosts from emerging as surprise winners after a "good test".
The Italian, whose team also won their home game against the Reds in last season's group stage, but lost the away tie to drop into the Europa League, said: "We come out of this match aware that this team can do well.
"It was just one victory, but yes, it has given us confidence, being able to match Liverpool is impressive as for me, they are the best team in Europe at the moment.
"It's proven that this team can perform very well, dig in and make sacrifices... but it's a long way to go. Now we must think about progressing to the knockout stages."
AGENCE FRANCE-PRESSE, THE GUARDIAN
