BELO HORIZONTE, Brazil (AP) -- Argentina coach Alejandro Sabella denied there was any power struggle going on with Lionel Messi ahead of the Group F match against Iran, saying he wasn't offended when his star player publicly expressed his views about team tactics.
Messi this week told reporters that he favours a more attacking formation than the one Sabella used in the first game against Bosnia-Herzegovina, which Argentina struggled to win 2-1.
But Sabella said there was ''nothing new'' in Messi's comments about how the team should play and praised morale within the Argentina camp.
''We don't have any problem. It didn't bother me at all,'' Sabella said. ''The atmosphere in the group is perfect.''
Dismissing speculation in Argentine media that Messi had demanded to speak publicly about the issue, Sabella said it was he who asked the Barcelona forward to talk to reporters.
Messi said he prefers the 4-3-3 formation that Argentina used in most qualifying matches than the more defensive 5-3-2 lineup that Sabella fielded against Bosnia.
Sabella switched to a three-man attack in the second half and he said that's the system he will rely on against Iran, who held Nigeria to a 0-0 draw in their Group F opener.
He also said he wasn't concerned about how his change of tactics was perceived by people outside the team.
''If you're not self-critical they say you are stubborn and if you are self-critical they say you are weak,'' Sabella said. ''I can't think about the outside when I make decisions. I think about the group that I command.''
Argentina practised Friday at its World Cup base on the outskirts of Belo Horizonte instead of in the Mineirao stadium -- Saturday's match venue -- because of concerns over the state of the pitch. Iran also practised off-site.