The Danish defender said: "We will do everything we can to be the best we can.
"But we accept we're being challenged by the best players in the world and even though it's at Celtic Park it will be a difficult game.
"The Barcelona game hurt. You could be disappointed and not move on but we have shown the character that needed to be shown.
"We have moved on and we are ready for the challenge again.
"All players are evaluating their game individually but the team is ready to do what it takes against Manchester City.
"It's about concentration. We need to be one step ahead of the others. They play at the highest level and we need to think a bit quicker.
"In the Nou Camp, Barcelona were doing things a bit quicker than us."