The Argentine has cast doubt over the host's chances of lifting the World Cup on home soil ahead of their quarter-final tie against Colombia
Felipe Scolari's side advanced to the quarter-finals after edging out South American counterparts Chile on penalties, and Maradona believes they must improve to have a chance against Colombia in the quarter-finals.
"Except for a few moments of brilliance from Neymar, Brazil have not looked like potential champions," said Maradona in his Times of India column.
"It was said that their defence is one of the best. Stoppers Thiago Silva and David Luiz, wing-backs Daniel Alves and Marcelo, with [Luiz] Gustavo and Paulinho as additional cover in midfield would not concede many goals. After three in four matches and many nervous moments in front of the goalmouth, this opinion has to change."
The 53-year-old also highlighted a distinct lack of flair and creativity in Brazil's team apart from Neymar, traits that have historically been entrenched in famous Brazil sides of the past.
He added: "I am concerned about the lack of creativity in their midfield. Normally, this is an area where Brazil score over their opponents. Other than Oscar, this team has no brilliant passer. Paulinho has flopped, Fernandinho has been okay. The forwards will struggle if they don't get quality supply from the midfield.
"Neymar will be tightly marked and will thus drop deep to find space, and unless the supply line is good, you are bound to get suffocated, like what happened against Chile. They have to find support for Neymar to sustain pressure in the attacking third."
Ahead of the quarter-final tie in Fortaleza on Friday, Maradona believes it is Colombia's James Rodriguez who will be the defining factor for both teams' fortunes.
"Colombia have been the most impressive South American side," said Maradona.
"In Rodriguez, they have found the most promising footballer of this World Cup. He is masterminding their progress.
"Without Gustavo, Brazil must keep him under strict vigil. How they do that might determine the outcome of this match."