Coach Diego Maradona and captain Javier Mascherano reassured fans that the squad were in good spirits and all 23 players were vying for a place in the team to face Nigeria in their Group B opener in Johannesburg on June 12.
But Maradona's supposed certainties about having found his team and tactics when Argentina beat Germany 1-0 in a March 3 warm-up in Munich no longer appear to be absolutes.
"The team will come out (of the practices) very few days before (the Nigeria match)," Maradona told a news conference at the squad's University of Pretoria base.
"I have 23 wild cats prepared to leave their skins on the pitch. With each training session it gets harder to decide."
Maradona said it did not bother him not to have any warm-up games arranged in the coming days before the tournament starts on June 11.
"I'm not concerned because our practices carry you to a level you might not reach in a match risking injury to one or other (player)," he said.
The less experienced players were making "a very big leap in quality" while the veterans were in optimum shape.
"We're going to reach a level that the (Argentina light blue and white striped) shirt deserves... Argentines should relax because to beat this team (rivals) will have to put all their beef on the grill," said Maradona using favourite imagery.
He suggested that those who did not believe Argentina would do well in the tournament were ignorant.
"Those who know about football in Argentina said we beat 'nobodies'," he said sarcastically, referring to the 5-0 victory over Canada in their farewell in Buenos Aires on May 24.
"We had a great farewell with Canada... Spain beat Saudi Arabia 3-2," he said without going into detail.
Argentina also face South Korea and Greece in their group.
