Leroy Sane says City never stopped believing, despite losing Nicolas Otamendi and trailing 2-1 with only five minutes remaining.
Sane and Raheem Sterling’s late goals tipped the axis the Blues’ way going into the return leg with the German winger citing three precious away goals as a crucial advantage.
“We knew it would be a tough game here, like it always is in the Champions League,” said Sane.
“In the end, we did it. We scored three goals away from home and that was the most important thing, to score goals away. Now, we’ll see what happens in the return.
“We were well aware of how difficult this would be. When Pep prepared the game, he already said we have to be careful.
“Schalke are a really tough team and it is a tough atmosphere and a tough stadium to come to.
“The Schalke fans are really loud and good; they push the team. We knew it would be tough.
“But we never give up. We always want to keep going, keep fighting. We know what kind of quality we have in the team.
“We know we will get chances. We have to wait for our chances and score goals and we did that today. It was not our best game, but we won and scored three away goals.”