Messi: We have only ourselves to fear
Messi missed a host of chances as the South Americans beat Nigeria 1-0 at Ellis Park on Saturday, and the current World Player of the Year believes his side should guard only against complacency.
"Argentina should only be afraid of Argentina," Messi said. "I say this with maximum respect to all the other teams but we have quality and talent.
"We must remain concentrated and go forward as we have been doing, training with care and staying united. We really should not be afraid of anybody."
The Barcelona forward believes that Diego Maradona's influence on his players has been crucial, adding: "Maradona is an exceptional motivator and to have him as a manager is an honour for us.
"He's close to us, he's one of us and he helps with his extraordinary experience. The attitude of the players has changed - and our team has an enormous margin of improvement."
Despite the reputation of the controversial coach, Messi believes Maradona's methods have had a positive influence on the squad.
"Everything has changed from the qualifiers," Messi said. "The approach has changed completely and the behaviour of the players.
"Before we weren't a group and we often played badly. We couldn't get the win and we were subjected to criticism. We are motivated, we train hard and we see the fruit of our work. We are a different Argentina."