Mayoral repaid Zidane's faith in handing him his chance on Sunday by scoring in the crucial victory at the Anoeta.
"For a No9 we are asking them to score goals and he has done a great job," said Zidane.
"Not only has he been a goalscorer, I am happy for him because he had his role in the team and it was not an easy field, it was a good rival, and we have made a great match."
Zidane added: "He's a good player, young man, but he can be and will have an important role, I'm very happy for him, he's had the opportunity to play and he's done well. I remain pleased with the work he has done."