Mexico will be ruing more suspect World Cup officiating after being incorrectly denied two goals in the first half of their Group A opener against Cameroon in Natal.
Giovani dos Santos was preferred to Javier Hernandez in attack, but found that fortune was against him as the assistant's flag twice ruled out his strikes.
The Villarreal attacker, formerly of Tottenham Hotspur, steered in a cross from Hector Herrera on 11 minutes, but was adjudged offside when he was in fact level with the last defender.
Cameroon set up very cautiously and rarely ventured forward, although Samuel Eto'o did clip the post with a shot from Benoit Assou-Ekotto's 21st-minute run and cross, before Dos Santos found the net again.
The 25-year-old converted at the back post after a 29th-minute corner was flicked on, but the Colombian linesman falsely deemed the deflection to have come off a Cameroonian body, leaving Dos Santos to be fractionally beyond the last man.
The African nation's early set-piece threat was negated by their own defensive tactics, but Mexico were also dangerous from dead-ball situations as Hector Moreno nodded wide when in plenty of space.
Questionable refereeing decisions marred Brazil's 3-1 win over Croatia as the tournament kicked off on Thursday.
