History favours the hosts in the group stage of the World Cup. They have played all the other three sides in the past.
Brazil's opponent in the June 12 opening match of the World Cup, Croatia, were their opponents in their first game in Germany in 2006 and a solitary Kaka goal made the difference. Cameroon faced Brazil in the US in 1994 and were thrashed 3-0, with the latter going on to win the tournament.
Brazil have met Mexico four times previously in the World Cup and have won thrice, while one game ended in a goalless draw. The last time the two countries met was in 1962, when Brazil won 2-0 and were eventually crowned the champions.
Brazil also comes into football's showpiece event with some momentum behind them after winning the FIFA Confederations Cup. They outclassed defending World and Euro champions Spain 3-0 in the final.
If one has to look at reputations, then Mexico should be the next best team.
But Mexico toiled in qualifying for the World Cup, needing a play-off against New Zealand to make it to Brazil after finishing fourth in the final CONCACAF qualifying group.
The squad also lacks star European names. Manchester United forward Javier Hernandez, or Chicharito as he is called, is probably the most well-known name. The surprise exclusion of former Arsenal striker Carlos Vela, who had an impressive season with Real Sociedad of Spain, has baffled all.
Others of interest in the squad are former Barca defender Rafael Marquez, Porto goalkeeper Hector Herrera and another former Catalan Giovani dos Santos, who currently plies his trade with Villareal.
Mexico will find a stiff competitor in Croatia, a side that has always had great individual players but whose ability to gel as a team has always been questioned.
With new coach Niko Kovac at the helm, one can be rest assured Croatia will bring some dogged determination to the pitch. The former Bayer Leverkusen, Hamburg and Bayern Munich defensive midfielder is well known for his steel, his spirit and leadership.
Croatia also has some big names like Luka Modric, Mario Mandzukic and Ivan Rakitic, all of whom have had a brilliant season for their respective European clubs.
Modric starred for Real Madrid in their 'La Decima', 10th European Cup, winning season.
Mandzukic was prolific for a Bayern team that did the domestic double and reached the semifinals of the Champions Legaue, beaten by the eventual champions.
The biggest find for Croatia, though, was Rakitic. The midfielder played a starring role for Spanish side Sevilla, who beat Benfica to lift the Europa League trophy. Croatia will also have the services of former Bayern Munich veteran Ivica Olic.
But the injury to Niko Kranjcar comes as a huge set-back for Croatia. He injured himself while playing for Queens Park Rangers in the Premier League and has been ruled out of the World Cup.
The odds on the 'Indomitable Lions' getting past the group stage are slim. The Cameroonians are not the force they were once. They sprung the biggest surprise in the 1990 World Cup, where they reached the quarterfinals.
One of Cameroon's most well known stars, Samuel Eto'o, is still is still there. But neither is he the striker who was scoring 30-plus goals every season for a marauding Barcelona nor are Cameroon the team that was most likely to spring a surprise.