Mannone spent last term on-loan at Hull City.
"I have improved in every part of the goalkeeper position. In my mind as well, I came back stronger and stronger," Mannone told Arsenal Player.
"Especially after the mistake at Olympiacos - it is never easy to come back, but when I have got my back against the wall, I don't mind.
"I just roll up my sleeves and try to work because I know I can do well.
"It is a good fight between the keepers because we know the level is quite high and you need to keep working and improve yourself to get the first spot."