It was no more than the Mexicans deserved after playing the more enterprising football and having two ‘goals’ by Giovani dos Santos controversially disallowed for offside in the first half.
Cameroon almost snatched a last-gasp equaliser but Guillermo Ochoa saved well from a firm header by Benjamin Moukandjo.
With Brazil and Croatia their other opponents in Group A, Mexico will be relieved to have claimed three points from a full-blooded encounter played in heavy rain at the Arena das Dunas.
A number of hefty challenges went unpunished throughout the game by Colombian referee Wilmar Roldan, but Mexico always looked the stronger side.
Peralta netted after 61 minutes and with Dos Santos also shining, the strike pair justified their selection ahead of Manchester United’s Javier Hernandez.
Both sides had entered the competition with question marks over their readiness.
Mexico – having had four coaches in the past year and only qualifying via a play-off against New Zealand – boasted little form having lost recent friendlies to Bosnia-Herzegovina and Portugal.
Cameroon’s preparations had been chaotic with the squad arriving in Brazil a day later than planned after a row over bonuses with their national federation.
The African players had also been under fire from their fans and media after failing to accept a symbolic flag from their prime minister.
Those issues seemed to be hampering Cameroon as they started poorly and rarely threatened to improve upon a record that has seen them win just once at a World Cup finals since 1990.