The stage was the FIFA Confederations Cup Brazil 2013 and the hosts were taking on Mexico in their second group match. As the Brazilian national anthem boomed out in Fortaleza’s Estadio Castelao, the fans sang with such ferocity that, even once the music stopped, they collectively decided to continue belting out the rest of the verse – the entire world agape with amazement at the start of what is now a Seleção tradition.

What went on that evening is just one of a host of incidents that have contributed to the growing fervour that has surrounded each meeting between Brazil and El Tri in recent years. And with the two sides set to lock horns once more in Fortaleza on Tuesday, FIFA.com was on hand to sample the pre-match atmosphere.

Passions running high
It is by no means an exaggeration to say that the way Brazil’s players and supporters seized on the national anthem had a hand in O País Pentacampeão winning the competition. Having gone into the tournament under a cloud, the hosts followed up their opening win over Japan by sinking Mexico 2-0, a winning run that continued through to their emphatic 3-0 success over world champions Spain in the final.

Since that Mexico game, the Brazilian faithful have repeated the anthem tradition at every encounter, while the trend has even extended to other South American nations. “We’ll never forget that, ever,” said goalkeeper Julio Cesar a few days ago. “It gave us a boost and ended up being a key ingredient at our games. I’m sure we’ll see the same thing happen at Fortaleza once more and that’s a huge motivator for us.”

While the Brazil fans are undoubtedly passionate, their El Tri counterparts do not lag behind. Indeed, some 10,000 Mexicans are estimated to have made the trip to Fortaleza for this game and have already been involved in one of the most moving episodes of the 2014 FIFA World Cup™ so far.

Not long after the squad arrived in the city and with the players relaxing in their hotel, suddenly, in the distance, could be heard the sound of chanting, which grew louder and louder. Intrigued by the commotion, the footballers went out onto their balconies to be greeted by the sight of thousands of fans swarming around the streets outside – chanting their names and singing Mexico’s traditional FIFA World Cup ditty, Cielito Lindo (Beautiful Sky).

So impressive was the scene that the players and coach Miguel Herrera decided to join in the party, moving down to a terrace just metres away from the assembled supporters. Some took photos, others pulled off their shirts and whirled them around their heads and, once the hubbub had died down, there were no shortage of Twitter entries recounting a thrilling event for everyone involved.

Rivalry on the pitch, friendship off it
Ever since Mexico witnessed first-hand Brazil’s unforgettable class of 1970, a solid bond of respect and mutual admiration has formed between the two sides. It is not unusual to see Mexicans support Brazil when not playing against Los Aztecas and vice versa, despite the fact that A Seleção no longer enjoy the dominance they once held over their fellow Latin Americans.

According to Luiz Felipe Scolari himself, Mexico have become something of a "bête noire" for Brazil in recent times, with El Tri recording significant victories over their illustrious opponents at the Copa America, FIFA Confederations Cup, Men’s Olympic Football Tournament, FIFA U-20 World Cup and the FIFA U-17 World Cup during the past 15 years.

In a further new development ahead of their Brazil 2014 clash, battle is already waging in the virtual arena. Just days ago, the host nation’s Twitter account challenged their Mexican counterparts to see who could go into the match boasting the most followers – with high-profile individuals swiftly leaping to the defence of both causes.

For the hosts, that man was superstar striker Neymar, who urged his fans to “Follow @CBF_Futebol and help beat the Mexican national team on Twitter!” The No10’s 11 million-plus followers will no doubt have had a significant impact, while El Tri responded with another two heavyweights in coach Herrera and Mexican President Enrique Pena Nieto. “We’ll beat Brazil in followers and out on the field. Let’s follow @miseleccionmx and make sure #Mex feel our support,” said the latter.

So, the stage is set for what could prove another enticing clásico. The question remains, who will take the honours on and off the pitch?