The Spain international signed a four-year deal with the west London side earlier this month after Chelsea agreed a £32m deal with Atletico Madrid.
He is a guy whose life was not easy, nobody gave him anything for free and he always had to fight a lot
Costa, who endured a miserable first World Cup, scored 27 goals in 32 appearances as he helped fire los Rojiblancos to the La Liga title.
And Mourinho, who led the Blues to a third-place finish last season, insisted that Costa is ready for the challenge of becoming Chelsea’s goal-scorer.
“I’ve known Diego since he came to Portugal from Brazil at the age of 17,” Mourinho is quoted as saying by Daily Mirror.
“He is a guy whose life was not easy, nobody gave him anything for free and he always had to fight a lot. He is afraid of nothing, ready for everything.
“What jumps immediately when you see him is his physical and psychological profile. It’s immediate, a big, strong guy, using his body, attacking spaces, holding up the ball and pressing people.
“But he’s much more than that. His movement is incredible, the intelligence is amazing, the choices he makes in terms of movement is fantastic.”
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