Hazard played under Mourinho during the Portuguese's second spell at Chelsea, winning a Premier League title in 2013/14.
But the pair enjoyed a famously combustible relationship during their time together, with Mourinho once telling a dressing room they were “playing with 10 men" thanks to Hazard's lack of defensive work.
Coming off the back of his worst season as a professional, Mourinho has rekindled the rivalry, claiming his poor attitude on the training pitch stops him from reaching the game's pinnacle.
Asked about his former charge, Mourinho told talkSPORT: “An amazing player with awful training.
“He gets on the pitch every morning and he doesn't work much. You can imagine what he could be if he was a top professional."