Striker Aguero said: "They're a difficult team, obviously. If you give them the time and the space to think, they will beat you.
"You always have to respect Barca and any team would respect that, but we had to pretend that it wasn't Barca and try to play how we know, and win, which was the most important thing."
With a passionate crowd feeding off City's stirring performance, and given the quality of the opposition, it felt like a landmark victory for the club.
City have faced a long a difficult journey to establish themselves among the elite but this win, perhaps more than anything on last season's run to the semi-finals, gave the impression they truly belonged there.
tiempo legend white Profiles Sergio Aguero
Aguero said: "I've experienced many different important nights, and this was another one that not only me but the whole team enjoyed.
"We also could feel the support from the fans and that was important for our confidence. It was a nice game for the memories."
mercurialx black Aguero did not get on the scoresheet himself but was highly influential in leading the attack. The Argentinian was surprisingly left out of the starting line-up in the defeat in Barcelona two weeks ago in a tactical move that backfired, sparking speculation about his future.
Manager Pep Guardiola has repeatedly dismissed suggestions he does not see Aguero in his future plans and the forward himself denies he was angry about the situation.
ace 16 purecontrol red The 28-year-old said: "I'm never angry. I respect every manager's decision. He said it was a tactical thing and I obviously respect that.
"When I went on the pitch I tried to give my best and then train hard to be ready for the next game. No-one was in a bad mood."
After having a strong early penalty claim denied and then falling 1-0 down, City could quickly have found themselves out of the game as Barca spurned a succession of chances.
But a Sergi Roberto error allowed Aguero and Raheem Sterling to tee up Gundogan's equaliser and City were transformed. In a compelling encounter, De Bruyne then put the hosts ahead and Gundogan notched the third after a flurry of activity that also Barca hit the bar through Andres Gomes.
new soccer shoes The ball did strike Aguero's hand from Jesus Navas' hard-hit cross before Gundogan scored his critical second but the forward claimed that was accidental.
X 16.1 sliver fg "I had my hand by my side and there was no intention to use my hand," he said.
The result meant Aguero finally got one over his Argentina team-mate Messi, the five-time world player of the year who destroyed City with a hat-trick last month.
There were rumours of a tunnel spat between the pair but they are recognised as two of the best friends in football and Aguero played this down, although there was no great exchange of pleasantries.
Aguero said: "We haven't talked. Whenever you lose you're not very happy. I know him well enough to know when he's bad, when he's good. Leo wasn't in the mood to talk and I respect that."
