Yet that switch made little difference, and Blaise Matuidi made the most of a mistake from Keylor Navas to dramatically level the scores at 3-3. There was contact from behind on Lucas Vázquez as he tumbled to the ground just yards from goal, but even so it appeared generous.
But with the tie heading towards extra-time, Madrid were awarded a penalty following Mehdi Benatia's challenge on Lucas.
Gigi Buffon, in possibly his last appearance in the Champions League, was livid at the decision, and his verbal volley aimed at Oliver earned him a red card.
Zidane told the postgame news conference that his team had suffered after conceding Mario Mandzukic's second-minute opener, but had kept believing and eventually achieved progress which was deserved over the two legs.
Another headed goal by Mandzukic after 37 minutes really had Los Merengues on the ropes, the Croatian only the second Bianconeri player to score a brace versus Madrid, the other being club legend Alessandro Del Piero in 2008.
Ronaldo's victor, which meant a 3-1 defeat on the night but a 4-3 aggregate victory, means Real edge one step closer to claiming a third consecutive European triumph, and fourth in five years. Soccer can be cruel, and it's beyond cruel that the one thing missing from the Italian's resume is a Champions League winner's medal.
Buffon had announced in October that this would be his last Champions League campaign unless his side won the final, after which he had meant to play in the Club World Cup. "We can be happy with that".
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"It was a game with a lot of suffering and reminded us that in football nobody gifts you anything, and you have to fight until the end".
Bale's night was up at half-time as he and Casemiro were replaced by Zidane's tried-and-trusted duo in Europe of Vazquez and Asensio.
The penalty was taken eight minutes into stoppage time as it took a while for Oliver to clear the Juventus players who were protesting against the decision.
But Vazquez was insistent that English official Oliver made the right call.
"I don't understand why they protested the penalty", Ronaldo said.
Mandzukic opened the scoring in the second minute by entering the area behind the Madrid defenders to head in a well-placed right-flank cross by Sami Khedira in what was the fastest ever goal conceded by Madrid at home in the Champions league.
If it was not for the heroics of the goalkeeper, the La Liga giants could have been behind by more in the first 45 minutes, when he stopped former striker Gonzalo Higuain from finding the net.