Bale has been a hot topic at the Santiago Bernabeu so far this term, with the 28-year-old becoming the target of jeers from some sections of Madrid supporters on more than one occasion this season.
But his goal in Sunday's 3-1 victory – a delicate finish after a 50-yard sprint – was his second in four league games this season and Zidane believes he proved a point with his performance.
"I'm very happy for him," Zidane told reporters. "There is a lot of talk about him, but he has demonstrated the player he is.
"It proved to be a great game, not only because of the goal. But I'm happy for the goal because he needed to put it in.
"It's not easy, after a 70 metre sprint. Technically he did it very well and, for me he's not even at his best.
"I know we're going to find [the real] Bale little by little. I know he can do a lot better, but we have to be patient, as I said before the game."
Zidane also reserved special praise for Borja Mayoral, who scored his first LaLiga goal in what his first league start in Spain since April 2016.
"He's a good player," Zidane said. "He's young man, but he could have an important role, so I'm very happy for him.
"He's had the opportunity to play and he's done well."