Manager Jurgen Klopp said Liverpool's defeat by Burnley was a "massive punch in the face" but took full responsibility for Thursday's 1-0 loss at Anfield.
The Reds seemed to be hitting their stride on 19 December when they took Crystal Palace apart 7-0, but have not won since then.
"It's a tough one, not easy to explain," Klopp told BBC Sport. "These boys are not the kind of person after a 7-0 to think 'we'll go like this', they worked hard tonight and it didn't happen.
"If something doesn't work, you have to try harder, more often, longer.