Bilardo, now Argentina's technical director of national teams, compared Messi's situation to that of Maradona when he was preparing Argentina for the 1986 Mexico tournament.
"I said (in 1986) let me have Maradona for 30 days and then we'll talk. Messi has to have a good World Cup and he can do it," Bilardo told the sports daily Ole in an interview published on Wednesday on www.ole.com.ar.
"I also had problems with Diego before going to Mexico (in 1986). I was asked why I'd put him in the starting line-up or gave him the captain's armband. I have the cuttings from four newspapers," he added.
"Diego talks a lot to him (Messi). He's one of the best players in the world and we have to get him to play to his best," said Bilardo, who is in Madrid for Argentina's friendly against Spain on Saturday.
Messi, a candidate for Europe's Ballon d'Or and FIFA World Player of the Year, has failed to show his brilliant Barcelona form with Argentina, who were in danger of failing to reach the finals for the first time since 1970.
Maradona has been the butt of criticism from Argentine media and fans over his team selection and tactics and Messi has also had a poor press for failing to reproduce his Barcelona form in a light-blue and white jersey.
"Argentina played well for the first 20 minutes against Brazil, against Ecuador, with Uruguay... and there were matches in which they didn't play well," Bilardo said.
"My team (in 1986) also lacked (cohesion) before going to Mexico. You go finding that with matches. The players know it and now Diego will work in order to find it."
Bilardo defended Maradona's choice not to train in the mornings despite the coach's complaints that he lacked practice time. Media said Maradona enjoyed his sleep too much and did not like getting up early.
"The same happened to me," Bilardo said. "If I trained in the morning, I was criticised because the matches were in the afternoon. The coach trains when he wants to. That's his right."
