Guardiola is convinced the Portugal midfielder can develop into a world class fullback should he persist.
"Matheus can be an incredible right-back," Guardiola said. "Because he's a holding midfielder with incredible physicality going back. If he's focused, he can become one of the best.
"It's a question of him now, we talked a lot about that. It's just about changing your mind and feel that you can feel that, because he has special attributes to play in the sides. In the last two or three games, he has played unbelievable."
City meet Aston Villa this weekend and Guardiola also said, “I know the pundits and specialists and the former players know what will happen after five games. I’m not able to do that.
“The first two or three games we were out and now it looks like Liverpool is already done but I tell you they will be back.
“Always you wait 10-15 games to know exactly what’s going on.
“Obviously Liverpool and Arsenal will be there, someone else will be there and hopefully we can be there too. ”