The Premier League leaders are bidding to reach the last four for the first time since 2016 as they take a 2-1 advantage to Borussia Dortmund for the second leg of their quarter-final on Wednesday.
City have suffered defeat in the last 16 and in three successive quarter-finals since Guardiola took charge of the club.
The City boss said: “Now is the time to make another step. Everyone wants it. The players want to do it again because they were sad when we were not able to go to the semi-finals and this an opportunity to prove ourselves.
Gundogan has great memories of his time at Dortmund and feels it is a shame the game will be played behind closed doors, although in this instance that may work to City’s benefit.
The 30-year-old, who won a Bundesliga title with Dortmund, said: “Facing Borussia Dortmund knowing that there is no crowd feels like it’s a bit of a disadvantage for Borussia Dortmund.
“I played there for five years and I know how incredible the crowd is and the support is and how loud it can be also in that stadium.
“It is the same for us in our stadium. There is something missing in football at the moment and we can’t wait to have crowds back.”