ALEX McLeish will be unable to field the same side against Mexico in the Azteca Stadium in Mexico City a week tomorrow as he does against Peru in the National Stadium in Lima on Tuesday night.

The heat, humidity, air pollution and altitude – Mexico City is 7,400 feet above sea level and the team will only arrive the day before the game in order to combat that – will all present problems for the national team.

But James McFadden, who failed to grace a tournament finals during his own Scotland career despite winning 48 caps, believes these games will be invaluable for those who are involved.

“If we were going into this game with our strongest team then we would fancy ourselves to go and win,” said the Scotland assistant coach.

“We are going to try and do that, but we also need to be realistic because we are trying players to see if they can step up. That’s not getting an excuse in early, it’s just the truth.

“The heat, the humidity, the travelling, the altitude, will all be a factor. We understand that. But the Peru and Mexico players will need to make some adjustments too and we know it will be a challenge. But our boys should go and enjoy it.

“It will be tough, the altitude for one. We have been advised that it will be impossible to recover from the first game to the second. That means if you play the first game you are not going to be ready to play the second, that’s how tough it’s going to be.

“It’s going to be hard, all of that. I don’t think it will be hostile, but both games are sell-outs and they’re both preparing to go to the World Cup. They’re not wanting to go and leave on a defeat. They will be fired up for it. We have some big players missing.

“But it’s not a case of ‘just going to turn up and see how it goes’. We are obviously going to prepare and do everything correctly, we will look at the opposition and come up with something that can beat them. But it will be difficult. Everything will be difficult.”

“We have taken all the advice on board. We don’t have enough time to acclimatise. It’s a new experience, but we could be going to a tournament in a few years time where we need to be ready for that.

“If we don’t win the game and something disastrous happens then we haven’t really lost anything and we have gained from the experience.”

McFadden added: “The way the game is nowadays you have to take what the sports scientists say on board. We won’t train for as long as we would have done over in Scotland, but it will be for intense periods.

“There is a lot of time in between, we as the management are aware of that. The players will need to find ways of filling the boredom and we will need to help with that. The facility in Peru is extremely good and there will be plenty for them to do.”