Martin O'Neill claims Nicklas Bendtner has matured during his time at Sunderland, with his performances backing up his supreme self-confidence.
The Denmark international has always believed in his own ability, but he has flattered to deceive at times on the field.
Sunderland saw something in him last summer, though, and snapped him up on a season-long loan from Arsenal.
O'Neill inherited the 24-year-old when he succeeded Steve Bruce at the Stadium of Light, and he has been impressed by the striker's attitude.
He believes Bendtner has come a long way since bursting onto the scene as a talented teenager and feels his recent showings prove that he is a top Premier League performer.
After seeing the Dane net the only goal of the game in Sunderland's 1-0 victory over Liverpool on Saturday, O'Neill said: "When he went to Birmingham as an 18-year-old, he was trying to pick the team after a week.
"He has enormous self-belief and it never seems to flinch no matter what he's done in the game.
"It's a wonderful thing to have - I wish I'd had it myself. If it's properly placed, it's fine. You can have all the self-belief in the world but you need the ability to go with it.
"Fortunately he has the ability and he's bought into the team ethos. Since I've known him over the last three months, he's actually concerned himself with the team and even more now since he's come back.
"He had a little spell out and might have realised then that the team has to come first.
"The goal will have given him a confidence boost, although I've chided myself because that's the last thing he needs.
"But he did very well. He's still not fully fit. He wants to play centre-forward but not always in the box. Don't tell him I said that.
"We have a few jokes at his expense but when he's strong and fully fit he is a handful."