Virgil van Dijk admitted Liverpool started badly and failed to improve as they suffered a mauling at the hands of Aston Villa.
The Premier League champions conceded seven goals as Ollie Watkins and Co ran riot.
Van Dijk, normally so reliable in the heart of the Reds defence, looked a shadow of his normal self.
And he said: "It is hard to lose in the way we lost tonight, first and foremost, you cannot take the credit away from Aston Villa.
"If we are looking at ourselves, you have to say that we were not 100 per cent at it from the start until he finish.
"The goals we conceded we should have done better but also the chances we had, because we had many, we should have done better as well. We should not have lost like we did and now it is key we stick together."
Asked why his side had failed to perform, Van Dijk added: "I don’t know, what I said before you cannot take the credit away from Aston Villa.
"We should have been more clinical in all aspects of the game. We have to be very hard on each other and we will be, but it is important not to go crazy or anything. But we have to step it up, the performance level between this and Arsenal for the league and today is too big. We are all responsible.
"I felt the gaps were too high, the second ball the battle was lost many times and their goals helped them a lot."
Liverpool boss Jurgen Klopp, meanwhile, was at a loss to explain his side's performance/
"I can't explain, I'm not sure, but I can tell you what I saw," he said.
"For different reasons Aston Villa forced all the mistakes we made, we played in their cards. Obviously with the first goal, with the second as well, the third massively, the free-kick and all these kind of things, then the game has a specific direction.
"[It was] absolutely unexpected but it happened; for me we put all of our rubbish things, mistakes, in one game.
"Last week Mr Keane said it was sloppy. It was not sloppy tonight, it was just bad. I have to admit that but I cannot change it now. I would love to have a training session tomorrow and speak about but the boys go out with the national team."
