Roy Keane has had his say on the debate that looks set to run for several more years.
Cristiano Ronaldo has done his reputation no harm whatsoever with the way that he's started the current World Cup campaign.
Ronaldo has scored four goals in two games for Portugal in Russia as he looks to guide his country to consecutive triumphs at major tournaments.
A hat-trick for the Portugal captain in their group opener against Spain last Friday was followed by a terrific header against Morocco on Wednesday afternoon, giving him the lead in the race for the Golden Boot, as well as the contest for the next Ballon d'Or award.
It's looking increasingly likely that Ronaldo will be able to hold off any challenge from perennial rival Lionel Messi this year and if he keeps up his level of performances for the remainder of the World Cup, Ronaldo could well gain an insurmountable advantage over Messi in the argument about who is the greatest footballer of all time.
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Speaking on ITV on Wednesday evening, Ronaldo's former Manchester United teammate Roy Keane had his say on the debate that has captured the football world and the Irishman revealed that he believes Ronaldo currently has an edge over the Argentine.
"There's been a great debate over the last few years between him and Messi, but I think over the last six months, I think he's gone up to another level," Keane said.
"He's up there on his own. The way he started the World Cup, the way he finished last season. How many times can we say it about him? His improvement, his attitude... A lot of it - it's not natural ability for Ronaldo. As brilliant as he is, I think it's just sheer hard work, determination, desire. He's got a lot of courage, wants to get in there, he's brave. I've said it before, the guy's a genius.
"I think given his form at the moment, the way he's started the World Cup, I'd have him ahead of Messi. and I never thought I'd say that because I love Messi as well."
