The Reds lost 4-2 against Tottenham in the Carling Cup at White Hart Lane last night.
“We can’t take many positives from that game,” said Agger.
“I think it’s easy to say that when you let the opposition score four goals, you won’t win the game.
“Our team performance was just not good enough. We were far from strong enough and we have to do better.
“But now we will think about improving against Bolton Wanderers on Saturday – that is all we can do.
“We take every game as it comes and must play a lot better than how we performed against Tottenham.
“Bolton are a physical and strong team so it will be a tough match for us, but we are focused on making improvements in every area.
“We definitely have to do better.”