Thiago Rodrigues Pereira climbs wearily into the air-conditioned sanctuary of the coach where I’m sitting. He's been at a music festival overnight and is tired after just one hour of sleep.
While his friends rested for longer, Thiago put on his Gremio shirt and made his way to the bus station for the three-hour journey south to Porto Algere.
"It's Gremio - Internacional," says the young lawyer. "I'd never miss it. It's the biggest derby game in Brazil."
It's ten in the morning and Thiago's day will go like this: After arriving in Brazil's sixth biggest city, he'll go to meet friends in a favela (informal housing) close to Gremio's new 60,000 capacity Arena stadium, which opened in 2012.
It's impressive -- think Arsenal’s Emirates or Athletic Bilbao's new San Mames -- except it has a standing terrace behind one goal where the atmosphere can be exceptional.
At their old stadium, fans used to run from the back of the terrace to create what they called “an avalanche”. That is banned at their new home, but a crush on the new terrace a month after it opened led to modifications.
After the game, Thiago will take a bus overnight to Santa Maria, his home city -- population 200,000 -- which was largely unknown outside Brazil until a year ago when a fire in the Kiss nightclub killed 242. Most of those that died were aged between aged 18 and 30.
"Everyone knew someone who died," said 24-year-old Thiago. "I lost six friends in the tragedy."
England and Brazil players wore black armbands when they met at Wembley a year ago to remember victims of the fire and commemorate the 55th anniversary of the Munich air disaster.
Thiago, with a Gremio tattoo on his shoulder, is living life to the full and can't wait for the game.
"I miss our old stadium, but it was old and the stands were 40 metres from the pitch because there used to be a running track," he says. "The arena is much better, with steeper, closer, stands."
Gremio fans think it's the best stadium in South America, yet it won't stage any World Cup matches. That honour will go to their rivals, Internacional.
Thiago shows pictures on his phone from previous Gre-Nal games, including those of Gremio fans marching two miles to Inter from their old home.
"Police were everywhere and kept Inter away from us," he says. "People closed their windows and shut their blinds on the walk because we were so loud."
He explains some of Gremio's songs about Internacional. None are fit for publication and all contain mendacious accusations and perceived slights. The two sides do not like each other. At all.
Thiago pays 90 BRL ($40) per month for his Gremio season ticket behind the goal. That includes state championship matches, Brazilian league matches and Continental matches.
As Gremio finished second in Brazil last year, they'll play in the forthcoming Copa Libertadores, a competition they won in 1983 and 1995. They also reached the final in 1984, and 2007, when they lost to Boca Juniors.
Inter are a big club too. Brazilian champions three times in the 1970s, the Colorado (red) were South American champions in 2006 and 2010.
The two sides have also had success on the world stage. In fact, Porto Alegre is one of the few cities in the world to have more than one world champion.
Gremio were Intercontinental Cup winners in 1983 when their legendary striker Renato Gaucho scored twice against SV Hamburg. 12 years later, led by Mario Jardel, they lost on penalties to Ajax.
Inter, meanwhile, beat Barcelona to win the 2006 Club World Cup. Four years later, they took 10,000 fans to the tournament in Abu Dhabi. Southern Brazil to Abu Dhabi is a long way.
Last season, though, was not a vintage campaign with Inter finishing 15th in the Brasileiro, after which they sold strikers Diego Forlan and Leandro Damiao to help with their financial situation.
Part of their problem was that they had to play away from their Beira-Rio home as it was redeveloped ahead of the World Cup.
The new Beira-Rio should open this Saturday; late, like almost every World Cup stadium. Like Brazil's other chosen new venues, it's beautiful and, unlike those in non-footballing cities, it's one which will be well used long after the tournament ends.
Inter count former Brazilian internationals Falcao, Taffarel, Fernandao and Dunga as their heroes. Of the current generation, Oscar and Pato both played there.
Gremio old boys include local lad Ronaldinho, but he isn't popular with fans who accuse him of running his contract down before moving to Europe in 2001.
Anderson and Lucas, two players who went to England's Premier League for Manchester United and Liverpool respectively, remain hugely popular after a play-off game at Nautico in the north of Brazil in 2005.
The winners would be promoted and the match was exceedingly tense. 35,000 home fans made life difficult for the visitors and celebrated as the home side were awarded a controversial penalty in the 75th minute.
The decision caused consternation among Gremio’s players, four of whom were subsequently sent off. It would be 11 vs. 7 for the last 15 minutes, starting with a penalty for the team with 11.
The penalty was saved, though and after the goalkeeper cleared upfield, Anderson spotted an opportunity. He controlled the ball, ran past several defenders and scored. Gremio’s number 17 was only 16.
The visitors held onto their lead for the final 15 minutes to clinch promotion. A film was made about the game, which became known as the “Battle of the Aflitos” and a book was written about it too.
Gremistas partied for days, with Anderson -- the man the club’s coach associated with having three mobile phones -- immortalised. He left for Porto in a seven million euro deal in 2006, where he continued to excel before his career slowed at Old Trafford.
Porto Alegre is a lakeside city of 1.5 million people and it's scorching on derby day with record temperatures nudging 40 degrees Celsius. The heat and holiday season mean many of the city's residents have escaped to the beaches, but Gremio and Inter draw their support from all over Rio Grande do Sul, the southernmost state of Brazil which borders Uruguay.
There's a city bus strike which will hit the crowd, but while Brazilian crowds are loud and colourful, they should be bigger. A Rio derby at the Maracana between Flamengo and Fluminense attracted just 18,000 last Saturday.
High ticket prices were blamed by the radio phone-in ranters but crowds in Brazil average just 15,000 in the Brasileirao in 2012; Australia's A-League boasts better numbers.
Champions Cruzeiro were the best supported Brazilian team last year with an average of 29,315 and Gremio were fifth with 22,301. Inter's stadium was being rebuilt, so their 7,708 figure is anomalous.
They normally attract similar crowds to their great rivals, but in the days leading up to the game, this writer met dozens of people who described themselves as Gremio or Inter "fanatics".
Few, though, actually go to matches. Like many in Brazil they're armchair supporters, yet the derby is headlines news in every newspaper for days and dominates the media landscape.
Both clubs know they're usually going to lose their best talents to Europe, but when the players do leave, they miss the colour of home.
I went to see former Inter and Brazil striker Nilmar last year and asked him about the two big Brazilian derbies in which he played.
"The rivalry is stronger in Porto Alegre, a real football city,” he says. “Everyone is either Gremio or Inter and you see flags everywhere. I played for Inter, but Gremio fans were okay with me because I wasn’t outspoken.
“Gre-Nal is the biggest game in Brazil, bigger than Flu-Fla even. The noise in the stadium is like no other, not in Brazil, not in Europe. It’s different in Sao Paulo because the city is bigger, not everybody likes football and there are many clubs."
The best Brazilians still end up in Europe, but no country produces so many homegrown talents.
The league is also hugely competitive -- there have been nine different champions since 2000 -- and Nilmar thinks one reason is because there are so many derbies.
"Derby results are unpredictable," he says. "In Europe the fans sit down and are respectful. In Brazil they stand and sing. There’s more noise in Brazilian stadiums, more obvious pressure because everything is exaggerated and in your face: the police, fans, media. That can be tough."
A strengthening Brazilian economy saw a strengthening league. Forlan, Adriano, Ronaldinho, Deco and Seedorf all went to Brazil and Neymar stayed at Santos longer than might have been expected before joining Barcelona. However, the currency has weakened from a 2011 high and the economy has slowed.
It's 90 minutes before kick-off and the scruffy bars by Gremio's new home are busy. They're on the edge of a favela which backs right up to the stadium. Thanks to a lick of paint, beer pumps and some fan friendly names, they've sprouted up and benefitted from the stadium's construction.
"Drinking here supports the local economy," says a Gremista called Giancarlo.
The alternative economy of car parking, ticket touts and merchandising that is thriving in the presence of the stadium, plus all that beer money, has seen property prices rise 30 percent in a year, although selling a shack which isn't supposed to exist is not entirely legal.
2,000 Inter fans are bussed in surrounded by high security and they make their way to the top tier. They too have equally pernicious songs about their rivals.
There's space for them: the crowd of 24,572 is just over a third of the Arena's capacity. It is likely to be higher when they meet in the national rather than the state league which both clubs dominate, though the crowd makes the noise of twice as many with chants of "Go Tricolour" and others declaring their love for Gremio.
The Inter fans are equally loud, with their drummers working the crowd. They're the first to celebrate as their side, whose best player is their captain, the former Argentinian international Andres D'Alessandro, take the lead.
As the sun sets behind the Guaiba River, Gremio, whose ranks include 20-year-old defensive midfielder Ramiro, a midfielder being watched by several big European clubs, equalise. The goal sparks big celebrations, but no avalanche.
"Did you enjoy Gre-Nal?" emails the indefatigable Thiago a day later.
It was hard not to.