Jurgen Klopp has detailed his frustration after Liverpool were held to a 1-1 draw with Napoli on Wednesday night.
Victory would have sent the Champions League holders through to the last 16 of the competition, but the Reds were forced to settle for a draw after Dejan Lovren had cancelled out Dries Mertens' opener.
The first-half goal from Mertens enabled the Italians to sit back and soak up the Liverpool pressure before Lovren finally restored parity from James Milner's corner in the 65th minute.
The European champions were unable to force a winning goal however and will now need to avoid defeat against Red Bull Salzburg in Austria on December 10 to book their passage into the knockout stages.
Klopp detailed the tactical approach from his opposite number Carlo Ancelotti after the game and admitted the Neapolitans' fighting spirit made it tough at Anfield.
See how Liverpool's draw with Napoli unfolded HERE
He said: "Carlo is a smart guy, Napoli might not be in their best moment so you set up rather defensively and try to deny the strengths of the opponent and use your skills on the counter-attack. That's what they did for their goal.
“I think they played a similar system against Cagliari so we knew it was possible.
“It’s not that I have problems to keep my arms down. It was clear that we wanted to finish it tonight. We knew long before the game that it would be difficult against Napoli. It was difficult last year, it’s always difficult. They’re a good side.
“Two things that shouldn’t have happened. They scored and Fabinho got injured. One problem we could solve with Gini (Wijnaldum) who played a really, really good game, but the other one caused us a problem. Napoli were up for a proper fight, and whoever sees Napoli play usually, this was a different approach tonight – scoring a goal and defending with all they have.
“We had to increase pressure, and we did. The last 15 minutes of the first half was good, like it should be. Second half, it was this normal game when you play against a quality side who defends with all they have.
“The problem was we had the wings open, we tried to use them with the crosses, but we crossed the ball too early most of the time. That’s why the goalie caught so many balls.
“We scored a goal, a really nice one and then we continued to chase the game. But it didn’t work out for us, and that’s how football is sometimes. You don’t always get the results you want.”
Fabinho, who was withdrawn with what appeared to be an ankle injury in the first half, will be assessed ahead of next week's Merseyside derby against Everton.
The Brazilian international will sit out Saturday's visit from Brighton through suspension.
