Liverpool manager Rafael Benitez accepted that his side had been made to pay for defensive errors in their 4-2 Carling Cup fourth round defeat at Tottenham Hotspur.
The Reds were 3-0 down at half-time at White Hart Lane and were unable to recover sufficiently to avoid a convincing reverse.
Benitez told the club's official website: "We didn't play well, that is clear. We made too many mistakes in defence and gave the ball away too easily.
"To concede three goals in the way we did at the end of the first half we must be disappointed.
"We were really poor at the end of the first half. If you make a mistake and concede just one, then okay you can change it and make things better in the second half, but to concede three goals made it very difficult for us.
"The commitment of the players was much better in the second half. We scored two goals and had other opportunities, but it was difficult because they were playing well on the counter-attack.
"For me the key is to play well, take your chances and not make mistakes in defence."
Meanwhile, Benitez defended his decision to rest a number of players with other competitions at the forefront of his thinking.
He added: "We had to use different players in this competition because you can't play the same ones in every game.
"We also have to think about the Champions League and the Premier League, which are our priorities, then the FA Cup."