The 23-year-old, who made his La Liga debut earlier this season, made it four goals in the Copa del Rey this term when he netted a treble against the Segunda B outfit at the Bernabeu.
Mariano's future in the Spanish capital is still far from secure, however, with Zidane responding "we'll see what happens in January" when questioned on the centre-forward.
"Mariano? I'm happy for his three goals and the work he's done. We'll see what happens in January with Mariano. He wants to stay, he's our player, had his chance and done very well," Zidane told reporters.
Mariano was a regular scorer for Real Madrid's C and B sides before stepping into the first-team picture.