The result leaves Portugal on just one point after two games, three adrift of group leaders Germany and the USA.
Yet the World Player of the Year insisted that World Cup victory was only an illusion for his side, which he feels may best be described as “average”.
“Maybe we're an average team," said the star forward. "It would be a lie to say that we are a 'top' team.
“We have many limitations and suffer from injuries such as with Pepe [who was suspended] and [Fabio] Coentrao. This limits us a lot.
“We knew we would have a tough group, with perhaps teams better than us.
“I never thought we could be world champions, we have to be humble and know our level. I'm not a hypocrite, I never thought we could win the tournament.”
Ronaldo refused to use his recurring injury problems as an excuse for his side’s less-than-convincing displays so far in the tournament.
"I don't want to justify myself by talking about my physical problems, that's water under the bridge," he said.
"I'm here, I'm fighting, I'm trying to do my best, I'm running, and obviously it's no use talking about my issues.”
The Real Madrid talisman also refused to blame a long club season on Portugal’s below-par performances in Brazil, and feels his side were never in it to win it.
"Obviously we had a very long season, but every team here did as well,” said the 29-year-old. “They were also playing the Champions League and cups and leagues, so it's something everyone else could point out as well.
"I don't think we lost the game because our players lacked attitude.
“Every team comes here to win. We knew we weren't favourites, we have never been."
Portugal face Ghana in their final group stage encounter on Thursday.