Carlos Tévez headed Argentina home from an offside position in the 26th minute, giving the Albiceleste a 1-0 lead over Mexico.
The goal came after Tevez, with no players between him and goal, headed home a Lionel Messi chip from inside the six yard box.
Messi had played a through ball for Carlos Tévez, who was kept onside at 18 yards by right back Efraín Juárez. Goalkeeper Óscar Pérez came out to meet Tévez as he came onto the ball, blocking the shot, with the ball some back out to the edge of the box. Messi ran into the ball and hit it towards the empty goal, where Tévez, whose momentum had carried him toward goal, headed the ball into the empty net.
The goal was initially counted before referee Roberto Rosetti discussed the call with his linesman. After a one minute delay after the goal, Rosetti moved toward the center circle to restart play, allowing the goal.
Argentina remains head of Mexico 1-0 in the 32nd minute.