Ronaldo arrives at training with a huge bruise under his eye

Perhaps harshly, Ronaldo received criticism for this as some suggested a player's looks are unimportant on the pitch, but Zidane insists he was simply trying to see how deep the cut was.

"It's happened now," Zidane said. "He just wanted to know how deep his cut was, that's all.

"I'm just telling you what he said in the dressing room, I'm not going to invent anything. I'm not here to do that.

"It is sewn up and he is training. If he's training with a black eye, that shows the most important thing [for Ronaldo] is to be on the pitch."

Zidane also urged fans to stop jeering maligned striker Karem Benzema.

Benzema was introduced for Borja Mayoral in the 64th minute with Madrid 3-1 up, as the Frenchman made his first appearance since El Clasico on 23 December (AEDT).

The 30 year-old was given a mixed reception by the Santiago Bernabeu crowd, though, with whistles and jeers audible among the applause when he entered the pitch.

Benzema has struggled for form this season, scoring just two LaLiga goals in 13 appearances, but Zidane does not think there is an excuse for not supporting your own team's players.

"It's true, a month ago he wasn't playing," Zidane told reporters at his news conference ahead of the Copa del Rey quarter-final second leg with Leganes. "He wanted to get back quickly and he's back with the squad now. The only thing he enjoys really is being out with us on the pitch, so it's good to have him back.

"But it's not good to see him getting whistled when he gets back. This has happened with him and could happen with others.

"What we need from the fans is that they're with us. Of course, they're within their rights; they've paid so can have opinions, but I want fans to be with us for 90 minutes.

"After the game, whatever happens, happens. But during the game I want them with us. Karim will be available tomorrow."