Jurgen Klopp was less than pleased with the penalty decision which helped Napoli to a 2-0 win over his Liverpool side in their Champions League group stage tie on Tuesday night.
Jose Callejon went down in the Liverpool box under minimal pressure from Andrew Robertson, but the well-placed referee gave a spot-kick, and the VAR official decided against overturning the decision.
That allowed Dries Mertens to open the scoring from 12 yards, in a game Liverpool had otherwise been largely comfortable in, and in the dying moments, they added a second goal to seal victory in Naples.
"For me, it's clear and obvious, no penalty, because Callejon jumps before he has any contact," Klopp said. "But we cannot change that so we have to be critical with ourselves. We did well in a lot of moments, we played a lot of good football but we didn't finish off.
"In the second half, we had this wild game, we were running, they were running. They've killed everybody on the pitch, started controlling again and then we've conceded a penalty.
"Of course that doesn't help and I've seen it now, I don't think that's a penalty."
Klopp was also unhappy with his misfiring forward line, whose link-up play was far below their usual standard and forced only two real saves out of Napoli goalkeeper Alex Meret across the 90 minutes.
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"We controlled it in moments, but we had not enough chances in the end," Klopp said. "What you saw was a lot of respect from both sides, we both defended well and each ball we lost, or they lost, was immediately a threat.
"The last ball is the most difficult ball anyway, and if you are not in the right circumstances it's even more difficult. And so there were moments when we should have done better, for sure."