Oribe Peralta scored the only goal for Mexico in the 61st minute to give El Tri a crucial 1-0 win against Cameroon in their Group A match on Friday.
On their goal, a nice buildup from Mexico created a chance for Giovani Dos Santos. His shot forced Cameroonian goalkeeper Charles Itandje into action, but the rebound fell right at Peralta's boot. He delivered, putting Mexico in front.
Previously, Mexico had two goals controversially disallowed off the boot of Dos Santos.
Mexican goalkeeper Guillermo Ochoa preserved the win for Mexico with a fantastic late save to keep El Tri ahead.
Next up for Cameroon is a difficult fixture against favoured host nation Brazil on Tuesday, while Mexico take on Croatia on Wednesday.