The German, who scored twice in the clash, feels the triumph broke down a mental barrier for the Blues, in addition to aiding their hopes of progression.
The Manchester Evening News’ Stuart Brennan reports: “He likened City's win to Borussia Dortmund's group stage win over Real Madrid in 2012, when Gundogan was on the bench for the German outfit.
“Victory inspired them to top the group – beating City along the way – before facing up to Madrid again, this time in the semi-final.
“And even though most backed Cristiano Ronaldo and Co to exact revenge, they were blown away 4-1 at Westfalenstadion, and Dortmund held on in the second leg to reach the final.
“Gundogan looks back on that group win as significant in psychological terms, and feels City's Barcelona win could stand them in good stead later in this campaign.”
Of Dortmund’s victory, Gundogan recalled: “That was very important. After that, we were sure that these teams are like us – they have days when they win, and days when they lose.
“It was no longer a case of playing 'Big Madrid', and we have no chance, and we don't need to go into that game without confidence because we will lose.
“Especially after we beat them 2-1 in Dortmund at the group stage, we were sure that we could play a good team in this competition.
“You can compare Dortmund with now, but it takes development and is a quite long process to get to a final, so it's difficult.
“But we still have the chance to get to the next round, which is the most important thing. We can be very happy about that.
“We believed in ourselves before, even after the 4-0 defeat in Barcelona, that we could beat teams like them.
“The win was very important for the group stage, to be second.
“But there are two games to go. The game at Gladbach will be very tough but we want the points there as well.
“It is also about getting used to playing these teams all the time, more than once or twice.
“Then you know what it is to play these big games – how to prepare for the games, and how to handle specific situations within the game.
“It's all about having that experience, and we are getting there – there is still a way to go, but we are doing well.”
Meanwhile, our Wednesday night opponents have also been previewing the game, with Gladbach's Fabian Johnson insisting his side can ‘upset’ City.
Quoted in the Mirror, he said: “We know that we are capable of beating anybody when we are at home, and that includes Manchester City.
"Of course, it's going to be hard work. We will need to perform at our very best to compete with an opponent like them.
"The coach will prepare us for the match in the next few days and then we will give it everything on Wednesday night to keep the points here.
"City had an outstanding squad last season with many strong individual players. Now they also have a world-class coach in Pep Guardiola.
"I think you can see what he is trying to do. They now move it about even better than before and that obviously makes them more dangerous.
"We have to try to keep our heads up and be positive going forward."
The German outfit are enduring a difficult season so far and currently sit 13th in the Bundesliga. Captain Lars Stindl insists though the Foals can bounce back from their domestic crisis.
According to Deadline News, he stated: “We want to deliver a good home game against City and, if possible, seal third place in the group prematurely.
“That is our big goal - we believe we can seize this opportunity because we know what we can do.
“We have many games before us and we take every part as it comes.
“On Wednesday, a very different encounter awaits us under very different conditions.
“We have intense weeks ahead of us but we must stick together to try and make it better.”