Ronaldo has voiced his doubts over the quality of the current Brazil squad, suggesting that they are going to encounter many problems in the future.
After being eliminated from the quarter-finals of the Copa America, Dunga's side began their qualification campaign for the 2018 World Cup with a 2-0 defeat to Chile on Thursday.
And legendary two-time World Cup-winner Ronaldo does not think things are going to get any easier for the team.
"Of late, this is the team that gives the least hope to the fans. There are going to be more difficulties for the guys, and not for the others," Ronaldo said on SporTV.
"In the latest official competitions we have played, Brazil was worse [than Chile, Argentina, Uruguay and Colombia]."
However, one of Ronaldo's former international team-mates, Cafu, is far more optimistic about the future of the national team.
The former right-back, who captained Brazil to World Cup glory in 2002, is certain that they will be successful on the road to Russia but feels Tuesday's clash with Venezuela will be crucial to achieving that.
"Defeat is an outcome that can always happen against Chile, it may even happen on other occasions," Cafu told SporTV.
"I have no doubt that Brazil will qualify for 2018 and can rest assured.
"There will be other losses for the team, but the most important thing is the game with Venezuela - it's key.
"Brazil has to be respected - they will always be the favourite. Everyone plays to beat Brazil."