Jürgen Klopp declared himself "really, really sick" of Liverpool's defending after their 2-0 Carabao Cup defeat to Leicester City on Tuesday night.
The Reds crashed out in the competition's third-round, having previously reached the final and the semi-finals under Klopp, after second-half goals from Shinji Okazaki and Islam Slimani.
That came after a first-half in which Liverpool were well on top and enjoyed the better of the goalscoring opportunities with midfielder Philippe Coutinho's influence clear to see amidst a youthful line-up.
Liverpool waned after the Brazilian's half-time withdrawal and their defensive frailties cost them dear once again, Okazaki and Slimani's goals at the King Power Stadium both avoidable.
"It is always going to be difficult if we defend and concede goals like this"
That was certainly the view of Klopp, whom when speaking to journalists at his post-match press conference said: "After the first goal you saw the heads from Leicester [players] went up, so that was the biggest difference. It is a game-changer [in] moments like this."
The Reds boss explained that "you always have a chance to do it yourselves" but that "sometimes you are on the wrong side" of a game's momentum.
"That we conceded like this, that makes me really, really sick. That's hard," he continued. "Then the reaction, you saw a young team, we played one-twos on the left wing at 2-0 and then [Leicester] made a counter-attack."
Klopp insisted that Liverpool's mistake was ones he can "live with" because Ben Woodburn and Dominic Solanke, the two particular players exchanging the ball on the left, "together are about 34" in combined age.
He acknowledged that it "can happen" that mistakes are made by such young players, but touched upon their set-piece defending and how Liverpool once again struggled with the second ball.
"We had problems with this and now we had it with the second or third even, and then the throw-in," Klopp bemoaned.
The German also felt that the story of the game was "really easy to explain" and said: "We were the much better team in the first-half. We played good football, really good; didn't score, that's sometimes a part of football. We were unlucky in one or two moments, maybe not clinical enough in another."
"But as long as we concede goals like we conceded today again, then it is quite difficult," Klopp criticised, stating that Liverpool "should have scored three" but that "as long as you leave games open, you have to defend."
Talking about the goals Liverpool conceded in detail, the manager said that his side "always have to defend these situations better" as he analysed Leicester's opener which came from a "second ball after a corner."
He noted that it was "really close" to being offside and said Liverpool's back-line "need to make it more clear it is offside" by pushing up.
"You cannot defend always like we did against Arsenal and [launch] a [quick] counter-attack or whatever," he warned, saying that Liverpool "had to push up" but "didn't" and so paid the consequences.
Klopp also said: "The second one is a throw-in again and everyone can imagine, we know how to defend them but obviously we didn't do it. It doesn't feel too good but it's the truth that we are still a good football team."
The 50-year-old said that he sees Liverpool's quality but accepted that "it doesn't feel it at the moment" after exiting a cup competition in which they "wanted to go to the next round."
"Nobody was interested in who played the better first-half, everyone was interested [about] who will go through and we are not the team that will be in the next round for some good reasons," admitted Klopp.
Klopp: Decision-making, not ability to defend, is to blame for errors
Liverpool's persistent problems at the back - having conceded 16 goals in nine games across all competitions so far despite also keeping two clean sheets - have seen Klopp come in for criticism.
But asked whether he and his coaching staff practice defending situations in training, he responded that they "do it all the time" and that "defending is different things."
He expanded that they have to work on "common together defending" as well as "individual defending" plus "one-on-one situations" and "two-on-one situations."
"I don't think teams shoot a lot against us, I know they don't, they have not a lot of finishing situations," Klopp told reporters, saying that Liverpool even "defend really well in a lot of moments."
He explained that his team "know how to defend a set-piece" or "a throw-in" but that "you change two or three times and then in the end obviously it doesn't work."
Klopp added: "I'm in the boat, it’s not that I say [to the players] 'I told you and you don't know'. I feel really bad in the moment about this, of course it's not about not knowing [what to do] it's about doing it in that moment. That's hard in the moment."
He lamented that it "feels really hard in this moment" to be knocked out of the tournament "because of this" after "that performance in the first-half."
But Klopp accepted that they have been eliminated, saying: "We have to play like this. We are able. We made seven or eight chances and we still can play football. That's cool, [that's] good. But as long as you concede goals like this, it makes life really difficult."
On Coutinho being taken off at the break, Klopp confirmed "that was the plan before the game" because the Reds' No.10 "needs match time" after only making his return last Tuesday.
He revealed that it was never the plan to keep him on and that the playmaker was "not allowed" to "play again for 90 minutes or 60 or 70 or 80" - adding: "It was clear that 45 is the limit. We need to make him fit but we cannot push him through."