The five-time Ballon d'Or winner continued his remarkable form in front of goal with a brace to help Los Blancos to a hard-fought victory at the Ipurua Municipal Stadium, sealing the points with an 84th-minute winner.
Ronaldo has now scored 14 times in his last eight La Liga matches to well and truly put a slow start to the campaign behind him, and Zidane insists that Madrid can also overcome their poor start and still retain the La Liga title this season.
"[Ronaldo] is from another planet. He knows that he's going to score, he's very positive. He's a different and special player. His stats speak for themselves. He's a very good player and he's ours," Zidane told the club's official website.
"We've still got a chance of winning La Liga and that'll be the case until the end of the season,. It'll be tough, but sometimes, if you drop your guard you are made to pay. The important thing is to keep moving forward. We need to keep putting wins on the board if we want to achieve anything, that is what we will try to do.
"Today we managed it. We must enjoy this win, rest up for a few days, something we have not done for a while, and then focus on the Girona game. You've got to recognise the performance from Eibar, who put in a great display. They were the better team.
"They were excellent, particularly in the first half. It's a tough place to come and they're a good side that are enjoying a super season. We knew that we'd have to dig in, and although we struggled when on the ball, we fought together and showed good spirit to get the win. We're pleased with today."
Despite the win, Real Madrid remain in third place and 15 points adrift of leaders Barcelona.