Dos Santos opened the scoring in the 21st minute and Hernandez converted from the penalty spot in the 32nd minute to give the Mexicans victory in front of 84,519 spectators in Texas. The victory completed an unbeaten three-game tour of the United States for Mexico as they also claimed wins over Wales and Bosnia-Herzegovina.
Five-time FIFA World Cup™-winners Brazil are testing younger talent ahead of next month's London Olympics, while Mexico will begin qualifying matches on Friday for the 2014 FIFA World Cup that the Brazilians will host.
Brazil, with playmakers Neymar and Hulk in a starting role, were coming off a 4-1 rout of the United States last Wednesday. The Mexicans came into the game following 2-1 victory over Boznia-Herzegovina thanks to a Hernandez goal in the third minute of stoppage time. Mexico will open their Brazil 2014 qualifying campaign against Guyana in Mexico City on Friday.
Despite successive wins over Denmark and USA, Brazil were unable to grab a third and will hope for better when they take on arch rivals Argentina next Saturday in East Rutherford, New Jersey.
Dos Santos broke the deadlock in fine style when he picked up a pass from Pablo Barrera, beat Brazilian defender Danilo and cleverly lobbed his shot over Santos goalkeeper Rafael.
The former Barcelona player then turned provider for Mexico's second goal, taking advantage of a defensive mistake before being fouled by Juan inside the box. Hernandez made no mistake from the resulting spot-kick with a powerful right-footed finish.
Brazil tried to hit back, but superstar Neymar was well marked by Severo Meza and Carlos Salcido while Hulk and Leandro Damiao could not find much space either. Mexico goalkeeper Jesus Corona was called upon just before half-time to keep out a long-range effort from Oscar as Brazil tried to find a way through, but they still trailed by two goals at the break.
In the second half, Brazil coach Mano Menezes sent on attacking reinforcements in the form of Alexandre Pato and Lucas Moura but still Mexico held firm. Brazil's best efforts were a powerful cross-shot from Bruno Uvini and a shot from distance by Neymar that was saved by Corona.
Mexico had a chance to increase their lead in the 77th minute following a counter attack, but Hernandez was denied by Rafael. Highly-rated Brazil playmaker Lucas, whose side are preparing for the London Olympics, said: "We have to learn from this kind of game. We wasted many chances and they scored in the few they have. Mexico were a good test, they are a stronger team than USA and I think this game has served as preparation to face harder rivals like we will have in London.
Mexico forward Andres Guardado said: "Even though this isn't the main Brazilian team, it's always good news to defeat them."