Luis Fernando Tena's men held on to their narrow win despite a late onslaught by the Selecao to claim their first ever gold medal in the men's football at London 2012
Luis Fernando Tena's side opened the scoring 29 seconds after kick-off as they pounced on a defensive mistake before Oribe Peralta fired in from the edge of the area.
Peralta doubled his and Mexico's tally for the afternoon with 15 minutes left of the match as he headed home a right-wing cross, and despite Hulk pulling one back in stoppage time, El Tri held on and claimed their first ever gold medal in the football.
Neither side made wholesale changes from their respective semi-final victories. Mexico were forced into one change as Giovani dos Santos was replaced by Hector Herrera after the Tottenham man could only take a place on the bench due to injury.
Brazil on the other hand remained completely unchanged, with Alex Sandro surprisingly keeping his place in the midfield instead of Hulk, while new Paris Saint-Germain signing Lucas Moura once again had to settle for a place on the bench.
The match started like lightning as Mexico took the lead inside 30 seconds. Rafael da Silva tried to play an intricate ball just inside to Sandro, but the Spurs man was dispossessed by Marco Fabian who fed the ball to Peralta, and the forward let rip from the edge of the area, burying his strike past Gabriel.
For a few moments the goal appeared to wake Brazil up, but Mexico soon had the ball back under their control with the Selecao struggling to get Neymar, Oscar and Leandro Damiao into the match.
It took 20 minutes for the tournament favourites to force Jose Corona into a save. Damiao found Oscar in the penalty area, and the Chelsea midfield faked to shoot before going for goal, but the experienced goalkeeper easily made the save.
Mexico were looking very solid at the back, with Brazil’s fancy flicks and backheels not coming off as they began to look increasingly frustrated.
Brazil’s attacking prolificacy forced Menezes into making changes, and just after the half-hour mark Alex Sandro was hauled off for his FC Porto team-mate Hulk as El Tri were looking more and more comfortable.
Javier Aquino and Marco Fabian were beginning to double-up on Rafael and the Manchester United man was struggling, with Aquino cutting inside the full-back before laying a pass off for Jorge Enriquez, but the Chivas de Guadalajara man's strike fizzed just wide.
Minutes after coming on, Hulk was trying his luck as he shot from 30 yards, but Corona got down to his left and palmed it away, before then stopping Damiao from a tight angle.
Brazil were coming into the game a bit more as half-time approached and Marcelo almost equalised as the Real Madrid man played a one-two into the area with Damiao, but at the vital moment he sliced his shot wide of Corona's post.
The anonymous Neymar finally showed signs of life in the final minute of the first-half as he cut inside and fired a powerful low strike just past the post, but the first part of Mexico’s job was complete as they went into the break in the lead.
The Samba Stars looked like men on a mission as they came out after the break, with Hulk looking in imperious form, while 20-year-old Neymar lead a team huddle himself before firing narrowly over from 25 yards out.
The Santos superstar was involved again a few moments later as he burst into the area, but his shot had all of the sting taken out of it by a block from the impressive Diego Reyes and Corona gathered easily.
Following a lively start to the second period, the match went through a patchy spell, with Mexico handing out some rough treatment to Neymar, while the forward should have equalised just shy of the hour-mark as the ball dropped to him 10 yards out, but he blazed it well over.
Despite hardly touching the ball since half-time, Mexico were inches away from doubling their lead in the 64th minute. Thiago Silva failed to deal with a long ball allowing Fabian to steal it ball off him, and although Gabriel challenged the winger, the ball sat up for the Mexican to produce an over-head kick that came back off the crossbar.
Brazil looked stunned and they were just as lucky four minutes later as Peralta had a goal chalked off for being offside, then three minutes after that a Fabian header went a whisker over as Brazil were living life very much on the edge and they would soon pay for that.
Menezes' men had looked poor at the back all day and with 15 minutes to go, a lovely cross from the right by Fabian was brilliantly headed into the bottom corner by Peralta after the Santos Laguna man drifted away from all Brazilian defenders, and Wembley erupted.
Although they were pressing desperately for a late goal, Brazil were struggling to break down the Mexico backline, with Hiram Mier and Reyes looking as impenetrable as ever.
Brazil's frustrations were obvious in the final minutes as the awful Rafael gave possession away to Fabian and then fouled the clever midfielder, much to the annoyance of Juan whose opinions did not please the young United defender.
In stoppage time Hulk was played through on goal and stroked the ball past Corona to pull a goal back, while Oscar headed agonisingly over when he should have scored from five yards out, but Brazil could not find the equaliser and Mexico held on for the win as the Selecao still cannot win gold in the men's football.