José Mourinho says he has helped Eden Hazard improve so much it is now inconceivable that Chelsea would sell the Belgian – even for "crazy" money. Reports in France claim Paris Saint-Germain are contemplating making a bid this month for the player Chelsea bought from Lille for £32m in June 2012. Mourinho says Hazard has become so important that his club would not let him go for any amount.

Hazard's talent has never been in doubt but in the early stages of this season it was not certain whether he and Mourinho would thrive together, as the midfielder's inconsistency and occasional defensive frailty frustrated the manager. His attitude was also questionable and Mourinho dropped Hazard for a Champions League match against Schalke in November after the player forgot his passport while returning from a break in France and missed training.

Mourinho says he convinced the 23-year-old to focus more and become "a complete player". He did this through "conversations, feedback, demanding more, following the way I think is the right way. Even if it's not the right way, it's the way he has to follow."

He said: "He has made progress in everything. He was known as one of the worst trainers. Now I would not say he is one of the best but he has become a good professional. He was known to have lots of quality, which he has kept, but was not very effective in terms of real production and he was a player without a defensive culture. I think he now works very hard for the team. He's not the player who does a fantastic action and then disappears from the game for 30 minutes. He's trying all the time to be influential in our game. He's getting the responsibility, thinking 'If I am a top player, I have to be there in every match'. It is a fantastic evolution for him.

"When we work the way we work, when the players know exactly what they have to do, it's easy for them and he is doing that. I cannot expect him to be the match-winner every game because it is not fair to put that kind of pressure especially on a player who comes in from the side and sometimes finds himself far away from the decision area but we are very happy with him."

Chelsea will go top of the Premier League, at least temporarily, if they win at Hull City on Saturday and Mourinho believes the demands of challenging for the highest honours have also inspired Hazard.

"He likes the responsibility and feels it is important that we are close to the title. It's a different pressure. If we are 20 points behind Arsenal and he scores three goals it means nothing. If we are one or two points behind and he scores the winning goal in a victory that pushes us to the top, that means something. This experience is good for him."

Hazard's fellow Belgian Kevin De Bruyne is set to leave Chelsea with the club close to agreeing a deal with Wolfsburg. De Bruyne arrived for £6.7m from Genk in January 2012 but has become irritated at his lack of first-team action. Chelsea are ready to sell for a big profit. Mourinho said: "He wants so much to go that maybe it's a good option to let him go in a very good deal for the club, by a financial point of view."