The 21-year-old has been strongly linked with a move to Stamford Bridge, and it appears a club-record £90 million fee has finally been agreed with Leverkusen.
Havertz has established himself as one of the Bundesliga’s rising stars, registering 12 goals and six assists in Germany’s top tier last season.
Ex-Turkey international Korkut – who managed a 17-year-old Havertz in the 2017/18 campaign – says the talented midfielder has the required mental fortitude to play for a top club.
‘This is possibly the most special thing about him, his mental power,’ Korkut told Sky Sports.
‘You will not see the difference in him whether he is playing against Ingolstadt or Real Madrid, whether he is playing to avoid relegation or win a championship. He will always plays the same and at a high level.
‘Even at 17, he did not have ups and downs. It was not about the coach being brave, it was about the player.
‘He gave me that feeling that he could play those big games and he could. He has this unbelievable mental strength. I do not know if it translates into English but he is like an ice man.
‘When you watch him now, you cannot tell if he is under pressure. I don’t know what he is feeling inside but he does not show it and that is an important quality if you want to be one of the best.
‘Playing for big clubs is different. It is about mental toughness. There are a lot of nice young players out there. But to play for the biggest clubs. To play for Bayern Munich, Manchester United or Chelsea, you need to have something more than just talent. This boy has that.
‘It is not about being able to shoot fantastically well or because he can play the final pass, even though he can do those things. It is because of these mental qualities. That is the difference.’
‘The most important thing now is for him to play for a bigger club than Leverkusen but he is already fantastically prepared,’ Korkut added.
‘He has played in the Champions League. He was the top player in the Bundesliga. He is ready to play for any team in the world. Improve? What can you improve? Sometimes it is best to leave players like they are.
‘I don’t want to say he is the perfect player because I do not know if the perfect player exists, but he has all the tools to be a big player for the next three or four years. Very big. The boy is special.’