Liverpool defender Joel Matip has admitted that his mistake in the Reds' FA Cup loss to West Bromwich Albion led to his side's downfall in the fourth-round tie.
Matip attempted to back-heel the ball from his own line after Jay Rodriguez had put West Brom 2-1 up, only to miss the ball and concede his side's third goal.
Roberto Firmino had given the Reds a lead with a chip, but Rodriguez's brace and Matip's own goal ensured Alan Pardew's side passage into the fifth round.
"We started in front, our offensive play was okay, but in the defence we had problems," the Cameroonian told Liverpool's website.
"Mistakes like my one kill every team. This mistake cannot happen, I have to clear this ball. In the first half, [conceding] three goals, it hurts every team. It was really hard to come back then.
"We have to do everything to turn things [around], to get in better shape and get better results."
Liverpool are back in action in Tuesday evening when they play Huddersfield Town in the Premier League at the John Smith's Stadium.
