'Messi-mania' has swept the world since the Argentine's four-goal demolition of Arsenal in Tuesday's Champions League quarter-final, reviving the debate about who is the best player.
Real's Ronaldo brushed aside attempts to compare him to the World Player of the Year.
"I'm taller than him, and wider than him," Ronaldo, the most expensive player in the world, joked at a news conference on Thursday.
"Everyone talks about Messi and me but we aren't the only people who are going to be playing. It's not an individual duel. We are very different.
"Messi doesn't play alone. His colleagues have to take some merit too. Those who understand football know what I mean."
Ronaldo, who has netted 18 league goals to Messi's 26 this season, was full of admiration for his counterpart.
"I think Messi's having a great season, scoring lots of goals, and I think he's among the best now and always will be," Ronaldo added.
"I'm doing a good job in my first year in Spain and I'm sure that in years to come here I will also be among the best."
Real are level on points with champions Barca but top on goal difference with eight matches left to play, so a victory for either side would be a massive boost to morale for the run in to the end of the campaign.
"It's going to be a great game because of the way the league stands, with the two teams on the same number of points," Ronaldo said.
"I'm sure we're going to win. (But) I would rather lose against Barca on Saturday and win the league."
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