Iran's defense was holding firm against Lionel Messi's Argentina to keep their World Cup match level at 0-0 at halftime in Group F on Saturday.
Iran nearly took a surprise lead in the fourth minute at Mineirao Stadium when midfielder Ashkan Dejagah delivered an inch-perfect free kick, but unmarked right back Jalal Hosseini couldn't direct it on target.
Iran started out by closing down the space for Argentina in midfield, but the South Americans began to dominate as the first half wore on.
Argentina's best chance came in the 22nd minute when Gonzalo Higuain set up fellow striker Sergio Aguero, but his curling shot was pushed away by goalkeeper Alireza Haghighi.
The keeper had earlier thrown himself at Higuain's feet to smother a shot in the 13th minute.