On one side is Brazil, featuring international stars such as Thiago Silva, Neymar, Oscar, Lucas Moura, Hulk and Marcelo. With five World Cup wins (having qualified for all 19 World Cups), eight Copa América titles, four Olympic medals and a bevy of other awards, they are perhaps the most famous team in the history of soccer.

On the other side is Mexico, a scrappy squad with only one player, Giovani dos Santos, who plays outside the North American country - and he now appears set to miss the final with a leg injury. Mexico have never won the World Cup, or even an Olympic medal in football. Already guaranteed a monumentous achievement in silver, Mexico's relatively anonymous side has the chance to upset the historic giants of the international game and go one better.

But they will need a stellar performance and a decent slice of luck - as their opponents have pulled out all the stops for this competition.

Brazil

Brazil has been on an absolute tear these Olympics, averaging three goals a game. The offensive juggernaut is hardly threadbare at the back, having conceded five goals in five games. Much of the credit lies with the strategy of manager Mano Menezes, also the head coach of the senior team, and the stellar play of goalkeeper Neto.

The pre-tournament favorites have improved in the course of the competition, conceding only two goals in their last three matches. They absolutely destroyed South Korea in the semifinals, winning 3-0, a scoreline that probably flattered the losers.

"We are here to win the gold medal," forward Leandro Damiao told Reuters after they beat South Korea. "We are Brazil - we are here for the gold."

That's truer at London 2012 than any previous Olmypics. Menezes and Brazil have been targeting this competition - often a footballing afterthought - as their last true chance to test their mettle before hosting the 2014 World Cup. Teenage prodigies like impudent forward Neymar and midfield speedster Lucas Moura were fast-tracked onto the senior team to prepare first for these Olympics, and by extension for the big games in 2014. Brazil were knocked out in the quarter finals at the last two World Cups, a performance that will not be tolerated on home soil.

Menezes is trying to prove that he is gearing up for the big test, and most importantly, that he should remain the man to lead Brazil into 2014.

Defender Rafael, whose club team is Manchester United, believes his team will be ready for the pressure of the final.

"We were confident, the coach was confident - and the final will be different to every other match we have played," he said.

Mexico

Mexico reached the final after delivering a 3-1 beat-down to a weary-looking Japan in front of more than 82,000 fans on August 7. The offensive outburst was Mexico's second-highest scoring result so far. Coupled with their tournament-leading defense, allowing less than one goal per game, "El Tri" are peaking at just the right time.

Javier Cortes has been fantastic coming off the bench, while striker Oribe Peralta and midfielder Marco Fabian are crisp passers in a team that moves the ball well. Dos Santos will be a huge loss, however, as the squad's big name and creative spark.

"I'm very sad. I will miss the final due to a muscle tear, now I just have to recover and support my teammates this Saturday," Dos Santos wrote in Spanish on his Twitter account after learning he'd miss the final.

Using a 5-3-2 formation in all but one match, Mexico's atypical three central defenders match up well against Brazil's exceedingly offensive variation of the 4-2-3-1 style. The main battle, then, will likely be between Brazil's offense and Mexico's defense.

What could give Mexico the edge, though, is their cohesiveness. With the Olympics being primarily an Under-23 competition with only three "overage" players allowed, it is sometimes difficult for managers to evaluate the talent of young players. Not so with Mexico. As almost all of Mexico's players play in the Mexican Liga MX, they are intimately familiar with each other's playing styles. Manager Luis Fernando Tena also has extensive experience coaching in the league, meaning the players were already familiar with his system before London.

After a disappointing 0-0 draw with South Korea in the tournament's opening match, Mexico found their stride, winning every subsequent game.

Crowning achievement

No matter what happens in Saturday's final at Wembley Stadium ("The temple of soccer" as Brazil's Menezes calls it), the result will be historic: for all their accomplishments, neither Brazil nor Mexico has won Olympic men's soccer gold.

The pressure will be especially high for Brazil, as an expectant public and football federation will be watching the game with the World Cup in mind. Mexico, meanwhile, go into the game with the uncertainty of playing for the first time on such a large stage.

While more than 80,000 people will pack the stadium, up to a billion more may be watching on television: traditionally, the men's soccer gold medal match is the highest-rated event other than the opening ceremonies.

A fitting crowd, it would seem, for spectacular football fireworks.

Kickoff is Saturday at 15:00 GMT.