Mexico coach Ricardo La Volpe blamed his side's poor finishing for their 0-0 draw with 10-man Angola.
The Mexicans dominated the match but failed to find the decisive winner that would have put them on the verge of going through to the second round.
And La Volpe said: "We controlled the ball but when it doesn't go in, you end up as we did with a draw.
"As far as the next game is concerned, we will wait on the Iran and Portugal outcome before deciding our approach."
Mexico face Portugal on 21 June in their final match of Group D where a draw will guarantee them a place in the knockout stages.
Angola will need a victory against Iran in their final match to stand any chance of going through.