Edin Dzeko has admitted that he is unsure why Manchester City have struggled in the Champions League.
The Premier League holders are yet to win in the group stages of this season's tournament and could be knocked out if they lose their next match against Bayern Munich.
"It's difficult to say what's the problem, you know, because we had some great games in the Champions League, but for some reason we can't reach our top level — how we play in the Premier League — and we definitely have to work on it and try to learn how to play against teams in Champions League," he told Bleacher Report.
"When you think it will be easy, it's not; it's never easy there."
Man City's remaining Group E fixtures will see them host Bayern on November 25, before travelling to the Stadio Olimpico to face Roma on December 14.