An 'angry' Jurgen Klopp admitted he is worried by Liverpool's blip after they were beaten by Southampton on Monday night.
Klopp accused his players of throwing the game away after Danny Ings' stunning second-minute winner extended the champions' winless run to three games.
Saints are now four points off league leaders Liverpool, who could be overtaken by Manchester United before they meet at Anfield on Sunday week.
Southampton boss Ralph Hasenhuttl sunk to his knees, with tears in his eyes, after a 'perfect night' which ended with a first win over Liverpool for nearly four years.
Klopp said: 'I know they are great guys and players but they were not good tonight.
'When I think they should do better, I get angry. Not for long but I do. We don't have to make it bigger but it's big... (it's) all our fault. My fault but the boys had a hand too.'
He added: 'It's very frustrating because it's so unnecessary... we gave the game away in the first few minutes and after that we were not calm enough to create the opportunities to turn it around..!
Liverpool have now failed to score in their past two matches. On Monday night, they had to wait until the 75th minute for a first shot on target — not since December 2015 have they been so wasteful in a Premier League game.
'We are worried about that,' admitted Klopp. 'We know about the situation, we are not silly and we have to show a reaction 100 per cent.'
Klopp was also frustrated by the officials' failure to award his side two penalties in the second half.
'What Andre Marriner did with Sadio Mane today, I'm not sure if that's OK to be honest,' he said.
'I've heard that Manchester United had more penalties in two years than (we) had in five and a half years. I have no idea if that's my fault and I don't know how that can happen but that's no excuse for the performance.'
Hasenhuttl, by contrast, was still emotional in his post-match press conference.
'It's the perfect evening,' he said. 'It's the first time I took points against Jurgen, an amazing manager, a fantastic team... to do such a job today, I cannot be more proud of the work the guys put in.'
Ings said: 'It's really special... to get the result we did was huge.' On his brilliant finish, the striker added: 'Some would say it was a cross, I say it was a shot!'