Roy Keane doesn’t use the G word often but he couldn’t help himself on Wednesday night

Roy Keane is not one to get carried away with praise.

The former Manchester United captain was notoriously difficult to impress on the pitch and, now that he's ventured into the realm of punditry, he makes for an even tougher crowd. 100 per cent is the bare minimum that the Irishman will tolerate when it comes to effort and his almost unrealistically high standards mean that flattery is seldom a part of his analysis. So when Keano does come out with some positive feedback on a player, you'd better believe that he's deserving of it. It would be hard to deny that Cristiano Ronaldo is one of the greatest players in the world but, having seen the Real Madrid superstar's stunning showing in their Champions League quarter-final second leg victory over Bayern Munich, Keane used a term that is not often uttered by the current Republic of Ireland assistant manager. Ronaldo scored a hat-trick, the 41st of his Real Madrid career, to knock Bayern out of Europe and his performance has prompted his former teammate to laud Ronaldo as "a genius." "The guy is a genius, there's no getting away from it," Keane said on ITV the night after Real's dramatic 4-2 second leg victory at the Bernabeu. "You are talking about one of the greatest players ever to play this game. He is a joy to watch! "We keep talking about how hard it is to score goals. You look at his stats every season…the goals he scores, the assists, the guy is a genius. Simple as that." After going so far as to insist that Ronaldo "would probably be really good in goal as well," Keane's more cynical nature showed itself as he admitted he wasn't altogether sold on the subject of video assistant referees. https://twitter.com/JOE_co_uk/status/846995092070125568 Last month saw the latest trial of new technology in a friendly between Spain and France and it played a vital role in two key refereeing decisions as a France goal, originally given, was ruled out before a Spain goal was awarded after consultation with the official with the benefit of a replay. But Keane's not convinced.