Brazil, the hot favourites and desperate to win the only major football title to elude them, ended with the silver for the third time after Peralta's double - the first after 28 seconds - sent them crashing to defeat at Wembley.
Their players, who won all five matches scoring 15 goals on their way to the final, looked utterly crestfallen on the victory podium as their 60-year search for the Olympic gold, which looked certain to end here, continues at least until they host the 2016 Games in Rio de Janeiro.
However he played down that idea afterwards, saying: "Any coach must be ready to suffer the consequences of his results, but I do not think this defeat will have a negative impact on the maturing process towards the World Cup in 2014.
"The World Cup at home in two years, remains our goal."
"I don't know whether it is the greatest day in Mexico's football history but it is wonderful to know that Mexicans will be partying at home and in the United States, where they will be proud to be Mexicans," he said.
"I am so proud of my players, this is a truly great success."
Brazil's young side - the Olympics is essentially an under-23 competition with three over age players allowed - were stunned by Peralta's first minute goal which came after a mix-up between Sandro and Rafael.
They finally did concede late into added time when Hulk angled a shot home and then they survived a header from Oscar soon after when he should have equalised - but they held on for Mexico's first gold of the London Games and their first major international football title.
