Argentina led Bosnia 1-0 at halftime in the Group F opener for both teams on Sunday, capitalizing on an own-goal in the third minute by Bosnian defender Sead Kolasinac.
The ball bounced off the defender's foot and into Bosnia's goal after Lionel Messi sent a free kick from the left flank into the penalty area that Marcos Rojo headed toward the far post.
Argentina controlled the play in the first 10 minutes, but Bosnia — playing in its first World Cup — was on even terms after that.
Blue-and-white clad Argentine fans filled half of the famed Maracana stadium.
Argentina coach Alejandro Sabella dropped two attacking players in Gonzalo Higuain and Ezequiel Lavezzi from his lineup.
World Cup debutant Bosnia was led by striker Edin Dzeko.