Mourinho guided Chelsea to the Premier League title in the 2014/15 season, with Hazard being the Blues star player, scoring 19 goals in all competitions, which is still the most prolific the 27-year-old has been during his time at Stamford Bridge.
"Hazard is huge and I don't think even he knows how much he can still improve", Sarri told Corriere dello Sport (via Football Italia).
"If I'm now asked one coach with whom I want to work again, then I say: Mourinho".
After HLN questioned the comment, Hazard explained why Mourinho is such a great manager to work under.
Although Hazard acknowledged that Mourinho's playing style was not as adventurous as that of Manchester City boss, Pep Guardiola, he added that the perception he is overly defensive is unfair. Real Madrid, since the departure of their talismanic forward Cristiano Ronaldo, have looked absolutely out of sorts in front of the goal and the inclusion of a player like Hazard will definitely come as a big boost for them.
Madrid, meanwhile, have struggled under new manager Julen Lopetegui and find themselves in fourth place in the Liga table after four matches, while they're on a run of four games without a win in all competitions. "We had a team to get a lot of prizes".
"I will never clash with a club".
However, the following season was marred by poor performances and reports of friction between certain members of the squad and Mourinho, who left by mutual consent in December, 2015.
"If he went into Real Madrid tomorrow, I wouldn't wake up tomorrow and say "that's a surprise" - that's how good he is". We will see. I don't want to talk about this every day. We'd enjoyed all that success together, but this time we hadn't.
"He needs a move to Barcelona or Madrid to be up there, classed with the best in the world".
"I think [Chelsea manager Maurizio] Sarri has said to him, "give me your best for one year and then you can get your move"".