The 45-year-old spent four successful years at Nou Camp in a terrific spell in the club's history, yet his future striker joked he could not improve one Barca star
Guardiola was announced as the replacement to current City boss Manuel Pellegrini in February and will take the reins at the Etihad Stadium next season, ending his stay at Bayern Munich.
Aguero admits he discussed his arrival with Messi as early as in June during Argentina's Copa America campaign, although is unsure if even Guardiola could enhance his team-mate's game.
"This year I haven't talked about it with Leo, but when we were playing at the Copa America he was telling me about Guardiola," he told radio station, Independiente en la Uno.
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"He told me how much he had learned with him and I asked him "what did you learn, idiot, to kick the ball better?"
Aguero insists his City colleagues will, however, be able to learn off the revered coach and adapt to his unique style of play, though is focused on ending Pellegrini's reign with trophies.
He said: "It's pretty crazy that four months out you already know that your manager is going to leave and you also know who his successor is, but that's how it is for us.
"Hopefully we can win something so Pellegrini goes in the best way. And then we'll adapt to what Pep Guardiola wants."