The Los Blancos attacker has enjoyed an impressive campaign thus far, scoring three times in 13 league games for the Spanish outfit after stepping into the first-team set-up.
"He is on the verge of becoming an important player for Real Madrid," Mijatovic told Cope.
"He is the type of player who could mark an era at Madrid, I have no doubt about that. He is a youth player who has the potential to become a first-team regular without any problems."
The 21-year-old is contracted to Madrid until 2017.