The Selecao will need to defeat an impressive Cafeteros side in the World Cup quarter-finals to keep their hopes of winning a sixth title alive.
Jose Pekerman’s side were one of only three teams who progressed from the second round in normal time with Brazil requiring extra time and penalties to defeat Chile.
World Cup winner Ronaldo is hopeful that Luiz Felipe Scolari’s men can beat Colombia in Fortaleza but the 37-year-old is remaining cautious.
"We Brazilians are resigned to suffer a lot, as against Chile, because Colombia play really well and they’ve revealed in the course of the tournament the talent of James Rodriguez,” Ronaldo told Gazetta dello Sport.
“He is a very special boy. Of course I hope we will be successful, and I have a fair amount of confidence. But I'm not sure.”
One of the players who has made the difference for the Selecao so far in the World Cup has been Neymar.
The 22-year-old Barcelona forward has scored four goals in the competition, one behind James, and has seemingly handled the pressure of steering Brazil through the tournament with ease.
Ronaldo has praised Neymar for dealing with the expectations thrust on his shoulders by the fans so well and believes he could fire Brazil past Colombia.
"He has responded very positively to the expectation. He has the character to be a great champion - not just the technical skills that we already know about.
“Tonight, the whole world will be watching the game, yet he is quiet, almost relaxed. Let's face it: until this time he and [Lionel] Messi have been crucial because Brazil and Argentina are not exceptional as a whole, but they’ve gone forward."
On a possible Brazil-Argentina final, Ronaldo said: "It would be an amazing gift in the history of football, because so far there has never been [this final] and you would not find a better place to celebrate than in the Maracana. But the road is still long.”
The other quarter-final clash on Friday will be played out between France and Germany in Rio de Janeiro.
Ronaldo believes that Joachim Low’s team will triumph at the Maracana and hopes that striker Miroslav Klose will score and surpass his own record as the all-time leading goalscorer at World Cup finals.
"These are two teams that in four matches played very well collectively,” he said.
“It is a World Cup classic. I see Germany as the favourites, also because they have Miroslav Klose in their squad, who has joined the club of 15 World Cup goals."