The match official awarded a 93rd minute spot-kick after Mehdi Benatia had brought down Lucas Vazquez inside the box.
While the Juventus players protested the decision furiously and Gianluigi Buffon got sent off in the process, Ronaldo believes Oliver made the right call.
"I don't understand why they are protesting," he said, as quoted by Marca.
"Lucas was tackled from behind and if they don't give him the penalty, it's a goal."
Zidane echoed the sentiment of his superstar, but insisted he never talks about the match officials.
"I'm not going to say anything to him, I'm not interested in what Guardiola says," the Frenchman said.
"We went through last year and won the Champions League, but I never mess with the referees, and I've had the chances to do so.
"I never get involved, and in any event, it was a penalty."