Hazard - who has started just two games since January - has therefore faced criticism from Real Madrid fans over his failure to stay fit and has reportedly turned up overweight to both of his pre-seasons at the Estadio Santiago Bernabeu.
Former Blues team-mate John Obi-Mikel told The Athletic in March that the Belgium international 'did not like to train hard' when he was in the Premier League.
Mourinho spent more than two years with Hazard at Chelsea before the Portuguese boss' second spell at Stamford Bridge was brought to an end when he was sacked in December 2015.
And speaking to talkSPORT, Mourinho agreed with the former Nigeria international and insisted Hazard 'doesn't work much' in training sessions and claimed he would be a much better player if he showed more professionalism in between matchdays.
'An amazing player with awful training,' Mourinho said of Hazard, who registered an assist for Kevin De Bruyne's goal in Belgium's 2-1 win against Denmark at Euro 2020 in Copenhagen on Thursday.
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.'
The duo have enjoyed an amicable relationship since Mourinho was sacked by Chelsea, with Hazard revealing in 2016 that he texted the Portuguese to apologise for the Blues underperforming and therefore sitting 16th in the table prior to his departure.
Source: All football news