Manchester City manager Roberto Mancini does not think goalkeeper Joe Hart would be as good as he is if he was not a bit "cocky".
Former Manchester United midfielder Roy Keane, working as an ITV pundit at England's World Cup qualifier in Poland in midweek, said he felt Hart had been a "little bit too cocky this year".
Asked about Keane's comments, Mancini said: "Every keeper is like this. It is important because if not, you should choose another position. If you want to be a keeper you should be cocky."
He added: "Joe is a good guy, he works very hard for this, he wants to improve.
"Remember last week, (Wayne) Rooney on Twitter said Joe Hart is the best keeper in the world. And now he is cocky.
"It is my opinion Joe Hart is the best keeper in England and one of the best in Europe and sometimes the keeper can make a mistake, but that is normal."
Keane suggested that Hart was not facing enough competition for his place with club or country and may therefore take "his eye off the ball".
"There's a fine line between confident and cocky, and I think he's been a little bit too cocky this year," the Irishman said.
Mancini dismissed those concerns, even though Hart has only kept one clean sheet for City this season.
The Italian said: "Joe is strong enough for this. He knows he is one of the best but if you want to continue to be the best you should work very hard. Everyone can make a mistake, it is impossible to be perfect. Only Mario (Balotelli) is perfect every day!"