Real Madrid won the first-leg of their Champions League round of 16 tie 3-0 on Wednesday night, with Fede Valverde hitting a hat-trick.
“Against teams like Real Madrid you know that as soon as you lose the ball that they’re just waiting to play a counter attack and then they score,” Doku said.
“They scored three goals and then it’s difficult to come back because they played very defensively, but I feel like if we scored the first chances that we had it’s a different game.
“(Gigio Donnarumma’s penalty save) helped us massively, we’re still confident.
“Obviously we have a game against West Ham before, but we trust our qualities and we know that at the Etihad it’s also a different game.
“We’ll need our fans to help us and if they can score three goals why can’t we?”