Uruguay vs Argentina: Best of mates
Security checks: two
Attire: no club colours
Plastic bottles: prohibited
Flags: allowed, but no poles
So reads the official information for home fans ahead of the battle of the River Plate - Uruguay against Argentina at the Centenario Stadium.
The final directive needs it's own clarification. Rather than assuring the Uruguayans that they can go with an amigo, it is assuring the locals that they can take their 'mate' - pronounced ma-tay.
Were it any other way, there'd be uproar.
Both Argentines and Uruguayans drink a lot of mate, basically a type of tea that you drink through a metal straw and share with others, but the thirsty charruas are the heavyweight champions.
They drink it while they drive, while they wait for relatives to arrive at the airport, while they work, while they walk, and perhaps even during more intimate moments, although that's just speculation.
A Uruguayan without a thermos flask under one arm, sipping away on their mate is an embarrassment to the nation.
The receptionist at Argie Bargy's hotel couldn't confirm whether drinking mate had been banned on buses.
He did think it sounded like a good idea, though, because someone could easily do themself some serious damage if the bus braked at the wrong moment.
The story with all the gory details that we were told is clearly the stuff of urban legend then.
So the celestes (light blue) and albicelestes (white and light blue) go to battle.
The two nations almost went to a real war over a papermill not so long ago, but the blockade put up in protest over the mill has been lifted to ensure fans can travel to the game.
These derbies have famously come under scrutiny in the past, when the match seemed more like a kick-about between, ahem, mates, ensuring both got the result they needed.
There'll be no favours tonight though. Both need a win to guarantee qualification. Defeat could leave them out of the play-offs and out of the World Cup.
The bookies have decided that Uruguay are the favourites. Argentina haven't won here since 1976 and Maradona's performance in the dugout hardly inspires confidence.
Neither does playing a back four of centre-backs. Neither does playing a debutant in midfield for this crucial game. Neither does playing Mascherano on the right.
These are all possibilities ahead if the game. Go figure.
Meanwhile, and this isn't a joke, most Argentines want Leo Messi dropped for Martin Palermo.
Uruguay, on the other hand, have the madre of all chances to create one of the biggest upsets in World Cup history by preventing their neighbours from making the finals.
Coach Tabarez will stick with the same side that beat Ecuador at the weekend, and hope that Diego Forlan shakes off all the cotton wool he's been wrapped up in this week to lead the side's attack.
Such is the occasion that a special deal has been struck to broadcast the game live, and free, on national TV, only they got a little excited and now it will be shown on ALL local channels.
Think BBC 1, 2, ITV, Channel 4 and Five all showing an England game...
"Argentina have given me some great moments as a fan," wrote one local journalist this week, "but I really want to knock them out of the World Cup."
They'll never have a better chance.
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