Coping with high altitude
Outside South America there is little recognition of the difficulties of the continent's World Cup qualification campaign.
Winning the competition was relatively straightforward. The hard part was qualification.
Both of their teams lost in Bolivia.
This week, it was Argentina's turn - they were thrashed 6-1 in La Paz.
The current qualification campaign has featured 31 home wins to 10 away - this ratio of 3:1 is normal in South America - and highlights the enormous difficulty of playing away from home.
There are long and arduous journeys to undertake, at the end of which the visiting team is surrounded by an intimidating atmosphere.
There are huge differences of climate and conditions - and, of course, there is the factor of altitude.
At some 2,800 metres above sea level, Quito, Ecuador's base, is difficult.
Wayward finishing, superb goalkeeping and some luck meant that Brazil came back from Quito with a 1-1 draw last Sunday. But on the balance of play Ecuador could easily have won by the same 6-1 margin by which Bolivia inflicted the first defeat on Diego Maradona's Argentina.
At 3,600 metres above sea level, La Paz is the venue that everyone dreads.
There is no telling exactly how the unacclimatised player will react - genetic factors seem to determine that some feel the effects more than others. But as a general rule, it is reckoned that without time to acclimatise players lose over 30% of their athletic capacity.
The lungs struggle and they can't find enough oxygen to move freely over the pitch.
Given three weeks anyone can acclimatise. But in the modern calendar no-one has this time.
It is thought that the third day is when the effects are felt most.
So what nearly everyone does - as Maradona's team did on Wednesday - is move up to altitude just a few hours before the game. In this way the effects of extreme altitude are minimised.
This might make medical sense. But to my mind it makes little psychological or technical sense.
In the minds of the players it builds the problem into the size of a monster, and it gives no time for them to make an adaptation to conditions, how to change their game in response to the lack of oxygen, and to the fact that the ball flies far quicker through the rarefied air.
Doing it this way is also a crime against the goalkeeper, who is more exposed than anyone else by the rapid trajectory of the ball.
It is almost impossible to do what Maradona's Argentina tried to do - roll up and just try to play their normal game.
This is especially true against a Bolivia side that have found some form. They are not going to qualify, and their main objective at this stage of the campaign is to do well in front of their own public, especially against Brazil and Argentina.
Even before the Argentina game kicked off the Bolivian strike duo of Joaquin Botero and Marcelo Martins (known as Moreno in Brazil, where he played for a while) were the top scorers of the entire campaign.
The pair, plus some other key players, didn't even travel to Colombia for Saturday's match. Bolivia sent out a side searching for a 0-0 draw (they lost 2-0) while keeping their gunpowder fresh for Argentina.
So the Bolivia game is a one -off, as I suggested in my blog at the start of the week.
I wrote then that the extreme conditions meant that we would learn nothing about Maradona's Argentina from this game. On reflection, I'm not sure that is entirely correct.
There are certain steps that teams visiting altitude need to take.
The idea is to run as little as possible, so the team must stay compact, giving the man on the ball plenty of options for a pass.
They must not defend too deep - it stretches out the team and makes it easy for the home side to shoot from range - very dangerous at altitude.
Against Ecuador, altitude exposed Brazil's deficiencies.
"Brazil had almost no possession," wrote 1970 great Tostao, "because, literally, there was no midfield. Gilberto Silva and Felipe Melo (the central midfield duo) played like centre backs."
So Brazil were unable to take the heat out of the game - while Argentina were over-run from the first because of their defensive weaknesses.
Martin Demichelis and Gabriel Heinze are too slow a pairing in the heart of defence. And, as slow centre backs usually do, they dropped deep to give themselves time - and opened up the field for the rampant Bolivians.
This is an area of the team that Maradona will need to look at - with Juan Forlin of Boca Juniors a promising defender who might well be worth a look.
Maradona said that he felt all the Bolivia goals like knife wounds in his heart.
They should heal, but an awareness is growing that a bigger axe could swing - the one that stops Argentina going to the World Cup.
They currently lie fourth, the last of the automatic qualifying slots.
Leaders Paraguay have a foot in South Africa.
Brazil and Chile, second and third respectively, have easier run ins than Argentina.
Lurking just two points behind in fifth, the play-off slot, are old rivals Uruguay - Argentina's final opponents in October's last round, which could be very interesting indeed.