The Blues are preparing for Tuesday's battle with Barcelona on their US pre-season tour following their penalty shoot-out win over Paris Saint-Germain in their International Champions Cup clash at the weekend.
As the players get set to take on the European champions, Mourinho, who coached Ronaldo during his three years in charge at the Bernabeu Stadium, has picked out his Belgian midfielder as his star man.
Asked if Hazard was better than Real Madrid's Cristiano Ronaldo, the Portuguese told the Daily Mail: "Last season, yes. In spite of the fact that Ronaldo was fantastic. He was fantastic. He scored an incredible number of goals. "I am not saying he is not fantastic. I am just saying that, in my personal view, every football player in the world should understand that a team has to be in front and no titles."
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Hazard, who signed for Chelsea in 2012, scored 20 goals in all competitions last season for the Premier League champions and was voted the PFA and Football Writers' player of the year.
On comparing the 24-year-old Hazard with Lionel Messi and Ronaldo, Mourinho added: "Obviously it depends on the season they have. They have to win some titles, no? Football without titles is nothing. Messi won the treble. He won three competitions last year, he reached the Copa America final. He had a fantastic season for him and for his team. I don't like players or managers to win individual trophies without the team."
Despite Real winning the World Club Cup last December, Ronaldo failed to get his hands on any domestic trophies in Spain or in the Champions League.